CMP Compass Minerals International Inc - 10-K

ITEM 1A.    RISK FACTORS

We are subject to a number of risks that could have a material adverse effect on our business, financial condition, results of operations and the value of our securities. You should carefully consider the following risks and all of the information set forth in this Form 10-K. The risks described below are not the only ones facing our company. Additional risks and uncertainties not currently known to us or that we currently deem to be immaterial may also materially and adversely affect our business, financial condition or results of operations.

Risks Related to our Restatement and Internal Controls

Management identified material weaknesses in the Company’s internal control over financial reporting that resulted in errors in financial statements. If the Company fails to remediate the material weaknesses or experiences additional material weaknesses in the future, it may be unable to accurately and timely report financial results or comply with the requirements of being a public company, which could cause the price of the Company’s common stock to decline and harm its business.

Management identified material weaknesses in internal control over financial reporting in conjunction with the restatement described in the Explanatory Note of our Form 10-K/A, filed with the SEC on October 29, 2024. The description of the material weaknesses that were determined to exist as of September 30, 2024 and September 30, 2023 is included under Part II Item 9A of this Form 10-K.

A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected in a timely basis.

While we are taking steps to address the identified material weaknesses and prevent additional material weaknesses from occurring, it cannot be assured that the measures the Company has taken to date, and is continuing to implement, will be sufficient to remediate the material weaknesses or to avoid potential future material weaknesses. Accordingly, there could continue to be a reasonable possibility that the material weaknesses identified, or other material weaknesses or deficiencies identified in the future, could result in a misstatement of accounts or disclosures that would result in a material misstatement of the Company’s financial statements that would not be prevented or detected on a timely basis or cause us to fail to meet our obligations under securities laws, stock exchange listing rules, or debt instrument covenants to file periodic financial reports on a timely basis. Any of these failures could result in adverse consequences that could materially and adversely affect the Company’s business, including an adverse impact on the market price of its common stock, potential action by the SEC, shareholder lawsuits, delisting of the Company’s stock, potential covenant defaults, and general damage to its reputation. The Company has incurred and expects to incur additional costs to rectify the material weaknesses or new issues that may emerge, and the existence of these issues could adversely affect its reputation or investor perceptions. The Company maintains director and officer liability insurance, for which it must pay substantial premiums. The additional reporting and other obligations resulting from the material weaknesses, including any litigation or regulatory inquires that may result therefrom, increase legal and financial compliance costs and the costs of related legal, accounting and administrative activities.

Operational Risks

Our mining and industrial operations can involve high-risk activities.

Our operations can involve or be subject to significant risks and hazards, including environmental hazards, industrial accidents and natural disasters. Our underground salt mining operations and related processing activities have in the past, and may in the future, be subject to hazards such as industrial and mining accidents, fire, natural disasters, explosions, unusual or unexpected geological formations or movements, water intrusion and flooding. For example, MSHA considers our Cote Blanche mine to be a “gaseous mine” and, as a result, is subject to a heightened risk of explosion and fire. These potential risks include damage or impacts from pipeline and storage tank leaks and ruptures; explosions and fires; mechanical failures; earthquakes, tornadoes, hurricanes, flooding and other natural disasters; and chemical spills and other discharges or releases of toxic or hazardous substances or gases at our sites or during transportation.

These hazardous activities pose significant management challenges and could result in loss of life, a mine shutdown, damage to or destruction of our properties and surrounding properties, production facilities or equipment, production delays or business

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

interruption. Our insurance coverage may be insufficient to cover all losses or claims associated with our operations, including these operational risks.

Geological conditions could lead to a mine shutdown, increased costs, production delays and product quality issues, which could adversely affect results of our operations.

Our salt mining operations involve complex processes, which are affected by the mineralogy of the mineral deposits and structural geologic conditions and are subject to related risks. For example, unexpected geological conditions could lead to significant water inflows and flooding at any of our underground mines, which could result in a mine shutdown, serious injuries, loss of life, increased operational costs, production delays, damage to our mineral deposits and equipment damage. We have minor water inflows at our Cote Blanche and Goderich salt mines that we actively monitor and manage. Underground mining also poses the potential risk of mine collapse or ceiling collapse because of the mine geology and the rate and volume of minerals extracted, among other potential causes. We could also have a ceiling collapse in the brine wells used to extract salt for mechanical evaporation, which could increase costs and cause production delays.

Variations in the mineralogy and geology of our mineral deposits have limited, and could continue to limit, our ability to extract these deposits, increase our extraction costs and impact the purity and suitability of extracted minerals to create products for sale and to meet customer specifications. This could adversely impact our ability to fulfill our contracts, resulting in significant contractual penalties and loss of customers.

The results of our operations are dependent on and vary due to weather conditions and lake level fluctuations. Additionally, adverse weather conditions or significant changes in weather patterns could adversely affect us.

Weather conditions, including amounts, timing and duration of wintry precipitation and snow events, excessive hot or cold temperatures, rainfall and drought, can significantly impact our sales, production, costs and operational results and impact our customers. From year to year, sales of our deicing products and profitability of the Salt segment are affected by weather conditions in our markets. Any prolonged change in weather patterns in our markets, as a result of climate change or otherwise, could have a material impact on the results of our operations.

In addition, our ability to produce SOP, sodium chloride and magnesium chloride, from our solar evaporation ponds located near Ogden, Utah, is dependent upon sufficient lake brine levels in the Great Salt Lake and hot, arid summer weather conditions. Prolonged periods of precipitation, lack of sunshine, cooler weather or increased mountain water run-off during the evaporation season could reduce mineral concentrations and evaporation rates, leading to decreases in our production levels. Other factors such as state or federal actions to manage the salinity of the Great Salt Lake could also alter north arm lake levels and disrupt our evaporation production cycle, impact our access to ambient lake brine in the Great Salt Lake or increase our related capital expenditures and production costs. Similarly, in recent years drought, decreased mountain snowfall and associated fresh water run-off have reduced brine intake levels, impacting subsequent harvests in 2024 and 2025. Future occurrences of drought and/or reduced runoff could also impact mineral composition and our mineral harvesting process, amount and timing. Similar factors could negatively impact the lake level and concentration of sulfates at the Big Quill Lake, impacting the operations at our Wynyard, Saskatchewan, Canada, facility, and potentially leading to decreased production levels, increased operating costs and significant additional capital expenditures.

Weather conditions have historically caused volatility in the agricultural industry (and indirectly in our results of operations) by causing crop failures or significantly reduced harvests, which can adversely affect application rates, demand for our SOP products and our customers’ creditworthiness. Weather conditions can also lead to a reduction in farmable acres due to flooding, drought or wildfires, reducing the need for application of plant nutrition products for the next planting season, which could result in lower demand for our SOP products and impact sale prices.

Our operations are conducted primarily through a limited number of key production and distribution facilities, and we are also dependent on critical equipment.

We conduct our operations through a limited number of key production and distribution facilities. These facilities include our underground salt mines, our evaporation plants, our solar evaporation ponds and facilities and the distribution facilities, depots and ports owned by us and third parties. Many of our products are produced at one or two of these facilities. Any disruption of operations at one of these facilities could significantly affect production of our products, distribution of our products or our ability to fulfill our contractual obligations, which could damage our customer relationships.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

For example, our two North American salt mines together constituted approximately 70% of our salt production capacity as of September 30, 2025, and supply most of the salt sold by our North American highway deicing business and significant portions of the salt sold by our consumer and industrial business. A production interruption at one of our salt mines could adversely affect our ability to fulfill our salt contracts and our ability to secure future contracts in affected markets or other markets or could lead to increased costs to service customers from alternative supply sources. Our salt mines also have limited access ways and shafts and any inability to use these access ways and shafts could impede our ability to operate or cause a production interruption. In addition, we only have a limited number of distribution facilities in the markets in which we sell our salt products. Failure to have our salt products at a specific distribution facility when needed (for example during a snow event) could adversely impact our ability to fulfill our highway deicing sales contracts, resulting in significant contractual penalties and loss of customers.

Similarly, our plant nutrition product, SOP, is only produced at two locations: our solar evaporation ponds and facilities located adjacent to the Great Salt Lake near Ogden, Utah, and our facility near Big Quill Lake in Saskatchewan, Canada. SOP production from these facilities could be disrupted or negatively impacted by structural damage, as a result of dike failure or other factors, which could result in reduced sales. A production interruption or disruption at one or more of our facilities could result in a loss of customers, a loss in revenue or subject us to fines or penalties.

Our operations depend upon critical equipment, such as continuous mining machines, hoists, conveyor belts, bucket elevators, loading equipment, baghouses, compactors and dryers. This equipment could be damaged or destroyed, suffer breakdowns or failures or deteriorate due to wear and tear sooner than we estimate, and we may be unable to replace or repair the equipment in a timely manner or at a reasonable cost. If these events occur, we may incur additional maintenance and capital expenditures, our operations could be materially disrupted and we may not be able to produce and ship our products.

Our business is capital intensive, and the inability to fund necessary capital expenditures or successfully complete our capital projects could have an adverse effect on our growth and profitability.

In recent years, we have made significant expenditures on large capital projects, including a shaft relining project at our Goderich mine and upgrading the barge dock at the Cote Blanche mine. In addition, maintaining our existing facilities requires significant capital expenditures, which may fluctuate materially. We also may make significant capital expenditures in the future to expand or modify our existing operations, including projects to expand or improve our facilities (including new mine level development and mine expansion to access additional mineral deposits, or to augment our Ogden facility’s pond storage capacity) or equipment and projects to improve our computer systems, information technology and operations technology. These activities or other capital improvement projects may require the temporary suspension of production at our facilities, which could have a material adverse effect on the results of our operations.

Any capital project we undertake involves risks, including cost overruns, delays and performance uncertainties, and could interrupt our ongoing operations. The expected benefits from any of our capital projects may not be realized in accordance with our projections. Our capital projects may also result in other unanticipated adverse consequences, such as the diversion of management’s attention from other operational matters or significant disruptions to our ongoing operations.

Although we currently finance most of our capital expenditures through cash provided by operations, we also may depend on increased borrowing or other financing arrangements to fund future capital expenditures. If we are unable to obtain suitable financing on favorable terms or at all, we may not be able to complete future capital projects and our ability to maintain or expand our operations may be limited. The occurrence of these events could have a material adverse effect on our business, financial condition and results of operations.

We face numerous uncertainties in estimating our economically recoverable reserves and resources, and inaccuracies in our estimates could result in lower than expected revenues, higher than expected costs and decreased profitability .

A mineral is economically recoverable when the price at which it can be sold exceeds the costs and expenses of mining, processing and selling the mineral. Forecasts of our future performance are based on, among other things, estimates of our mineral reserves and resources. Our mineral reserve and resource estimates of the remaining tons of minerals in our mines and other mining properties are based on many factors, including engineering, economic and geological data assembled and analyzed by our staff and third parties, which include various engineers and geologists, the area and volume covered by our mining rights, assumptions regarding our extraction rates and duration of mining operations, and the quality of in-place reserves and resources. The reserve and resource estimates as to both quantity and quality are updated on a routine basis to reflect, among other matters, production of minerals from our mining properties and new mining or other data received.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

There are numerous uncertainties inherent in estimating quantities and qualities of minerals and costs to mine recoverable reserves and resources, including many factors beyond our control. Estimates of mineral reserves and resources necessarily depend upon a number of variable factors and assumptions, any one of which may, if incorrect, result in an estimate that varies considerably from actual results. These factors and assumptions include:

• geologic and mining conditions, including our ability to access certain mineral deposits as a result of the nature of the geologic formations of our salt mines or other factors, which may not be fully identified by available exploration data and may differ from our experience in areas we currently mine;

• demand for our minerals;

• current and future market prices for our minerals, contractual arrangements, operating costs and capital expenditures;

• taxes and development and reclamation costs;

• mining technology and processing improvements;

• the effects of legislation or interpretations thereof, or regulation by governmental agencies;

• the ability to obtain, maintain and renew all required permits;

• employee health and safety;

• historical production from the area compared with production from other producing areas;

• the indigenous interest and rights of the First Nation organization in the provinces of Saskatchewan, Ontario and Nova Scotia, and the related consultation requirements applicable to us in these provinces with First Nation, which may impact our ability to obtain permits, lease extensions, mine and conduct our business; and

• our ability to convert all or any part of our resources to economically extractable mineral reserves.

As a result, actual tonnage recovered from identified mining properties and revenues and expenditures with respect to our reserves and resources may vary materially from estimates. Thus, these estimates may not accurately reflect our actual reserves and resources. Any material inaccuracy in our estimates related to our reserves or resources could result in lower than expected revenues, higher than expected costs or decreased profitability, which could materially and adversely affect our business, results of operations, financial position and cash flows. Additionally, our reserve and resource estimates may be adversely affected in the future by interpretations of, or changes to, the SEC’s property disclosure requirements for mining companies.

Strikes, other forms of work stoppage or slowdown and other union activities could disrupt our business and negatively impact our financial results.

Nearly 50% of our workforce in the U.S., Canada and the UK is represented by CBAs. Of our 12 CBAs in effect on September 30, 2025:

• Six expired in fiscal 2025 (including our Cote Blanche mine), four of which were renewed/renegotiated and two are still in the process of being negotiated;

• Four will expire in fiscal 2026 (including our Goderich mine, which have 393 positions represented by a CBA); and

• Two will expire in fiscal 2027.

Unsuccessful contract negotiations, strained labor relations at any of our locations or other labor-related factors have in the past, and could in the future, result in strikes, work stoppages, work slowdowns, or other forms of labor disruption. These disruptions may lead to increased operational costs, delays in fulfilling customer commitments and reputational harm. Ultimately, they could adversely affect our financial condition, operating results and long-term strategic objectives.

Our production processes rely on the consumption of natural gas, electricity, diesel, and certain other raw materials. A significant interruption in the supply or an increase in the price of any of these could adversely affect our business.

Energy costs, primarily natural gas, electricity, and diesel represent a substantial part of our total production costs. Our profitability is impacted by the price and availability of natural gas, electricity, and diesel we purchase from third parties. Natural gas is a primary energy source used in the mechanically evaporated salt production process. We do not have arrangements in place with back-up suppliers. We use natural gas derivatives to hedge some of our financial exposure to the price volatility of natural gas. A significant increase in the price of energy that is not recovered through an increase in the price of our products or covered through our hedging arrangements, or an extended interruption in the supply of natural gas or electricity to our production facilities, could have a material adverse effect on our business, financial condition and results of operations.

We use KCl in our salt and plant nutrition operations. Large price fluctuations in KCl can occur without a corresponding change in the sales price of our products sold to our customers. This could change the profitability of our products that require KCl, which could materially affect the results of our operations. In certain cases, we also source raw materials from a sole

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

supplier and cannot guarantee that any supplier will be able to meet our requirements and any changes in their operations, including prolonged outages, could have a material adverse effect on our business.

Competition, Sales and Pricing Risks

The demand for our products is seasonal.

The demand for our salt and plant nutrition products is seasonal, and the degree of seasonality can change significantly from year to year due to weather conditions, including the number of snow events, rainfall, drought and other factors.

Our salt deicing business is seasonal. On average, in each of the last three years, approximately two-thirds of our deicing product sales occurred during the North American and European winter months of November through March. Winter weather events are not predictable, yet we must stand ready to deliver deicing products to local communities with little advance notice under the requirements of our highway deicing contracts. As a result, we attempt to stockpile our highway deicing salt throughout the year to meet estimated demand for the winter season. Failure to deliver under our highway deicing contracts may result in significant contractual penalties and loss of customers. Servicing markets typically serviced by one production facility with product from an alternative facility may add logistics and other costs and reduce profitability.

Our plant nutrition business is also seasonal. As a result, we and our customers generally build inventories during the low demand periods of the year (which are typically winter and summer, but can vary due to weather and other factors) to ensure timely product availability during the peak sales seasons (which are typically spring and autumn, but can also vary due to weather and other factors).

If seasonal demand is greater than we expect, or we experience increased costs and product shortages, our customers may turn to our competitors for products that they would otherwise have purchased from us. If seasonal demand is less than we expect, we may have excess inventory to be stored (in which case we may incur increased storage costs) or liquidated (in which case the selling price may be below our costs). If prices for our products rapidly decrease, we may be subject to inventory write-downs. Our inventories may also become impaired through obsolescence or the quality may be impaired if our inventories are not stored properly. Low seasonal demand could also lead to increased unit costs if our production levels are curtailed.

Variables impacting effective inventory management may adversely impact our performance.

Efficient inventory management is essential to our performance. We must maintain appropriate inventory levels and product mix to meet customer demand, while minimizing costs related to storing and holding excess inventory. If our inventory management decisions do not accurately align to demand or otherwise result in excess inventory, as has happened in the past, our financial results may be adversely impacted by markdowns, impairment charges, or impact to subsequent period production rates. Conversely, if we do not maintain enough inventory to satisfy the demand of our customers, we may lose business to our competitors. Any such inefficiencies in inventory management could negatively affect our operations and results.

Anticipated changes in potash prices and customer application rates can have a significant effect on the demand and price for our plant nutrition products.

When customers anticipate increasing potash selling prices, they tend to accumulate inventories in advance of the expected price increase. Similarly, customers tend to delay their purchases when they anticipate future selling prices for potash products will stabilize or decrease. These customer expectations can lead to a lag in our ability to realize price increases for our SOP products and adversely impact our sales volumes and selling prices.

Growers’ decisions to purchase plant nutrition products and the application rate for potash products depend on many factors, including expected grower income, crop prices, plant nutrition product prices, commodity prices, input prices and nutrient levels in the soil. Customers are more likely to decrease purchases and application rates when they expect declining agricultural economics or relatively high plant nutrient costs, other input costs or elevated soil nutrient levels. This variability can materially impact our prices and volumes sold.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Our products face strong competition and if we fail to successfully attract and retain customers and invest in capital improvements, productivity, quality improvements and product development, sales of our products could be adversely affected.

We encounter strong competition in many areas of our business and our competitors may have significantly more financial resources than we do. Competition in our product lines is based on a number of factors, including product quality and performance, logistics (especially in Salt distribution), brand reputation, price and quality of customer service and support. Many of our customers attempt to reduce the number of vendors from which they purchase in order to increase their efficiency. To remain competitive, we need to invest in manufacturing, productivity, product innovation, marketing, customer service and support and our distribution networks. We may not have sufficient resources to continue to make such investments or maintain our competitive position. We may have to adjust our prices, strategy, product innovation, distribution or marketing efforts to stay competitive.

The demand for our products may be adversely affected by technological advances or the development of new or less costly competing products. For example, the development of substitutes for our plant nutrition products that can more efficiently mix with other agricultural inputs or have more efficient application methods may impact the demand for our products. In addition, new production methods or sources for our products or the development of substitute or competing products could materially and adversely affect the demand and sales of our products.

Changes in competitors’ production, geographic or marketing focus could have a material impact on our business. We face global competition from new and existing competitors who have entered or may enter the markets in which we sell, particularly in our plant nutrition business. Some of our competitors may have greater financial and other resources than we do or are more diversified, making them less vulnerable to industry downturns and better positioned to pursue new expansion and development opportunities. Our competitive position could suffer if we are unable to expand our operations through investments in new or existing operations or through acquisitions, joint ventures or partnerships.

Inflation could result in higher costs and decreased profitability.

Our business can be affected by inflation, including increases in freight rates, prices for energy and other costs. Sustained inflation could result in higher costs for transportation, energy, materials, supplies and labor. Our ability to recover inflation-driven cost increases may be constrained by the terms of our contracts, the competitive nature of the bidding process, and the economic and industry conditions prevailing in the markets where we operate. Significant inflation presents a risk of materially increasing our costs and adversely impacting our profitability and overall financial performance.

Increasing costs or a lack of availability of transportation services could have an adverse effect on our ability to deliver products at competitive prices.

Transportation and handling costs are a significant component of our total delivered product cost, particularly for our salt products. The high relative cost of transportation favors producers whose mines or facilities are located near the customers they serve. We contract (directly and, from time to time, through third parties) bulk shipping vessels, barges, trucking and rail services to move our products from our production facilities to distribution outlets and customers. A reduction in the dependability or availability of transportation services, a significant increase in transportation service rates, adverse weather and changes to water levels on the waterways used for our products could impair our ability to deliver our products economically to our customers or expand our markets. For example, when the Mississippi river floods significantly or if water levels are significantly reduced by severe drought conditions (as they were in 2023), barges may be unable to traverse the river system and we may be prevented from delivering our salt products to our depots and customers on a timely basis, which could increase costs to deliver our products and adversely impact our ability to fulfill our contracts, resulting in significant contractual penalties and loss of customers.

In addition, diesel fuel is a significant component of our transportation costs. Some of our customer contracts allow for full or partial recovery of changes in diesel fuel costs through an adjustment to the selling price. However, a significant increase in the price of diesel fuel that is not passed through to our customers could materially increase our costs and adversely affect our financial results.

Significant transportation costs relative to the cost of certain of our products, including our salt products, may limit our ability to increase our market share or serve new markets.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Risks associated with our international operations and sales and changes in economic and political environments could adversely affect our business and earnings.

We have significant operations in Canada and the UK. Our fiscal 2025 sales outside the U.S. were 30% of our total fiscal 2025 sales. Our overall success as a global business depends on our ability to operate successfully in differing economic, political and cultural conditions. Our international operations and sales are subject to numerous risks and uncertainties, including:

• economic developments including changes in currency exchange rates, inflation risks, exchange controls, tariffs, economic sanctions, other trade protection measures and import or export licensing requirements;

• difficulties and costs associated with complying with laws, treaties and regulations, including tax, labor and data privacy laws, treaties and regulations, and changes to laws, treaties and regulations;

• restrictions on our ability to own or operate subsidiaries, make investments or acquire new businesses;

• restrictions on our ability to repatriate earnings from our non-U.S. subsidiaries to the U.S. or the imposition of withholding taxes on remittances and other payments by our subsidiaries;

• political developments, government deadlock, political instability, political activism, terrorist activities, civil unrest and international conflicts;

• uncertain and varying enforcement of laws and regulations and weak protection of intellectual property rights; and

• risks relating to epidemics and pandemics and effects therefrom.

A significant portion of our cash flow is generated in Canadian dollars and British pounds sterling and our consolidated financial results are reported in U.S. dollars. Our reported results can significantly increase or decrease based on exchange rate volatility after translation of our results into U.S. dollars. Exchange rate fluctuations could also impact our ability to meet interest and principal payments on our U.S. dollar-denominated debt. In addition, we incur currency transaction risk when we enter into a purchase or a sales transaction using a currency other than the local currency of the transacting entity. We may not be able to effectively manage our currency risks. For more information, see Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Effects of Currency Fluctuations and Inflation,” and Part II, Item 7A, “Quantitative and Qualitative Disclosures About Market Risk.”

In addition, we may face more competition in periods when foreign currency exchange rates are favorable to our competitors. A relatively strong U.S. dollar increases the attractiveness of the U.S. market for some of our international competitors while decreasing the attractiveness of other markets to us.

Conditions in the sectors where we sell products and supply and demand imbalances for competing products can impact the price and demand for our products.

Conditions in the North American agricultural sectors can significantly impact our plant nutrition business. The agricultural sector can be affected by a number of factors, including weather conditions, field conditions (particularly during periods of traditionally high plant nutrition application), government policies, tariffs and import and export markets.

Demand for our products in the agricultural sector is affected by crop prices, crop selection, planted acreage, application rates, crop yields, product acceptance, population growth, livestock consumption and changes in dietary habits, among other things. Supply is affected by available capacity, operating rates, raw material costs and availability, feasible transportation, government policies, tariffs and global trade. In addition, the demand and price of our SOP products can be affected by factors such as plant disease.

MOP is the least expensive form of potash fertilizer and, consequently, it is the most widely used potassium source for most crops. SOP is utilized by growers for many high-value crops, especially crops for which low-chloride content fertilizers or the presence of sulfur improves quality and yield, such as almonds and other tree nuts, avocados, citrus, lettuce, tobacco, grapes, strawberries and other berries. Lower prices or demand for these crops could adversely affect demand for our products and the results of our operations.

When the demand and price of potash are high, our competitors are more likely to increase their production and invest in increased production capacity. An over-supply of MOP or SOP domestically or worldwide could unfavorably impact the prices we can charge for our SOP, as a large price disparity between potash products could cause growers to choose MOP or other less-expensive alternatives, which could adversely impact our sales volume and the results of our operations.

Similarly, conditions in the Salt sector can significantly impact our Salt segment. These conditions include weather conditions as well as import and export markets. Supply and demand imbalances can be caused by a number of factors, including weather conditions, operating rates, transportation costs and global trade.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Financial Risks

Our indebtedness and any inability to pay our indebtedness could adversely affect our business and financial condition.

We have a significant amount of indebtedness and may incur additional debt in the future. As of September 30, 2025, we had $845.8 million of outstanding indebtedness, which are further described in Part II, Item 8, Note 10. Long Term Debt and Finance Lease Liabilities of our Consolidated Financial Statements. We pay significant interest on our indebtedness, with variable interest on borrowings made under both our revolving credit facilities and account receivable securitization facility based on prevailing interest rates. Significant increases in interest rates will increase the interest we pay on our debt. Our indebtedness could:

• require us to agree to less favorable terms, including higher interest rates, in order to incur additional debt, and otherwise limit our ability to borrow additional money or sell our stock to fund our working capital, capital expenditures and debt service requirements;

• impact our ability to implement our business strategy and limit our flexibility in planning for, or reacting to, changes in our business as well as changes to economic, regulatory or other competitive conditions;

• place us at a competitive disadvantage compared to our competitors with greater financial resources;

• make us more vulnerable to a downturn in our business or the economy;

• require us to dedicate a substantial portion of our cash flow from operations to the repayment of our indebtedness, thereby reducing the availability of our cash flow for other purposes;

• restrict us from making strategic acquisitions or cause us to make non-strategic divestitures; and

• materially and adversely affect our business and financial condition if we are unable to meet our debt service requirements or obtain additional financing.

In the future, we may incur additional indebtedness or refinance our existing indebtedness. If we incur additional indebtedness or refinance, the risks that we face as a result of our leverage could increase. Financing may not be available when needed or, if available, may not be available on commercially reasonable or satisfactory terms. Any downgrades from credit rating agencies such as Moody’s or Standard & Poor’s may adversely impact our ability to obtain financing or the terms of such financing.

Our ability to make payments on our indebtedness, refinance our indebtedness and fund planned capital expenditures will depend on our ability to generate future cash flows from operations. This, to a certain extent, is subject to general economic, financial, competitive, legislative, regulatory and other factors that are beyond our control. There can be no assurance that our business will generate sufficient cash flows from operations or that future borrowings will be available to us under our revolving credit facility in an amount sufficient to enable us to make payments with respect to our indebtedness or to fund our other liquidity needs. If this were the case, we might need to refinance all or a portion of our indebtedness on or before maturity, sell assets, reduce or delay capital expenditures or seek additional equity financing. Our inability to obtain needed financing or generate sufficient cash flows from operations may require us to abandon or curtail capital projects, strategic initiatives or other investments, cause us to divest our business or impair our ability to make acquisitions, enter into joint ventures or engage in other activities, which could materially impact our business.

The agreements governing our indebtedness impose restrictions that may limit our ability to operate our business or require accelerated debt payments.

Our agreements governing our indebtedness contain covenants that limit our ability to:

• incur additional indebtedness or contingent obligations or grant liens;

• pay dividends or make distributions to our stockholders;

• repurchase or redeem our stock;

• make investments or dispose of assets;

• prepay, or amend the terms of, certain junior indebtedness;

• engage in sale and leaseback transactions;

• make changes to our organizational documents or fiscal periods;

• create or permit certain liens on our assets;

• create or permit restrictions on the ability of certain subsidiaries to make certain intercompany dividends, investments or asset transfers;

• enter into new lines of business;

• enter into transactions with our stockholders and affiliates; and

• acquire the assets of, or merge or consolidate with, other companies.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

The credit agreement governing our senior secured credit facilities also requires us to maintain financial ratios, including a consolidated interest coverage ratio and a consolidated first lien net leverage ratio, which we may be unable to maintain. As of September 30, 2025, our consolidated first lien net leverage ratio (as calculated under the terms of our credit agreement) was 0.01x. We would be in default under our credit agreement if our consolidated first lien net leverage ratio exceeds 2.75x as of the last day of any quarter through the fiscal quarter ended September 30, 2025, stepping down to 2.5x for the fiscal quarter ended December 31, 2025 and thereafter.

Various risks, uncertainties and events beyond our control could affect our ability to comply with the covenants, financial tests and ratios required by the agreements governing our indebtedness. If we default under our agreements governing our indebtedness, our lenders could cease to make further extensions of credit, accelerate payments under our other debt instruments (including hedging instruments) that contain cross-acceleration or cross-default provisions and foreclose upon any collateral securing that debt as well as restrict our ability to make certain investments and payments, pay dividends, repurchase our stock, enter into transactions with affiliates, make acquisitions, merge and consolidate, or transfer or dispose of assets.

If our lenders were to require immediate repayment, we may need to obtain new financing to be able to repay them immediately, which may not be available or, if available, may not be available on commercially reasonable or satisfactory terms. Under these circumstances, we might not have sufficient funds or other resources to satisfy all of our obligations.

We are subject to tax liabilities which could adversely impact our profitability, cash flow and liquidity.

We are subject to income tax primarily in the U.S., Canada and the UK. Our effective tax rate, tax expense, and cash flows could be adversely affected by changes in the mix of earnings in jurisdictions with differing statutory tax rates, changes in the tax laws and regulations and the discovery of new information in the course of our tax return preparation process. Our effective tax rate could also be adversely affected by changes in the valuation of deferred tax assets and liabilities. We are also subject to audits in various jurisdictions and may be assessed additional taxes as a consequence of an audit.

A Canadian provincial tax authority has challenged our tax positions and assessed additional taxes and interest on us, which are described in Part II, Item 8, Note 8. Income Taxes of our Consolidated Financial Statements. These tax assessments and future tax assessments could be material if the disputes are not resolved in our favor. Also see Part II, Item 8, Note 18. Subsequent Event for discussion of subsequent event concerning settlement of tax dispute for 2002-2018.

In the ordinary course of our business, there are many transactions and calculations that could be challenged by taxing authorities. This includes the values charged on the transfer of products between our subsidiaries. Although we believe our tax estimates and calculations are reasonable, they have been challenged by taxing authorities in the past. The final determination of any tax audits and litigation may take several years and be materially different from our historical income tax provisions and accruals in our consolidated financial statements. If additional taxes are assessed as a result of an audit, assessment or litigation, there could be a material adverse effect on our financial condition, income tax provision and net income in the affected periods as well as future profitability, cash flows and our ability to pay dividends and service our debt.

If our customers are unable to access credit, they may not be able to purchase our products. In addition, we extend trade credit to customers and the results of our operations may be adversely affected if customers default on these obligations.

Some of our customers require access to credit in order to purchase our products. A lack of available credit to customers, due to global or local economic conditions or for other reasons, could adversely affect demand for, and sales of, our products.

We extend trade credit to our customers primarily in the U.S., UK, Mexico and Canada, in some cases for extended periods of time. If these customers are unable to repay the trade credit from us, the results of our operations could be adversely affected. Our customers may be unable to repay the trade credit from us as a result of supply chain disruptions, market conditions in the agricultural sector, adverse weather conditions and increases in prices for other products and inputs that could increase the working capital requirements, indebtedness and other liabilities of our customers. We may not be able to limit our credit and collectability risk or avoid losses.

We are subject to financial assurance requirements and failure to satisfy these requirements could materially affect our business, results of our operations and our financial condition.

In connection with our dispute of tax assessments made by Canadian provincial tax authorities (described in more detail in Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Investments, Liquidity and Capital Resources”, and Part II, Item 8, Note 8. Income Taxes and Note 18. Subsequent Event of our Consolidated

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Financial Statements), we are required to post and maintain financial performance bonds. In addition, as part of our business operations, we are required to maintain financial surety or performance bonds with certain of our North American deicing customers and to fund reclamation and site cleanup following the ultimate closure of our mines and certain other facilities. We incur costs to maintain these financial assurance bonds and failure to satisfy these financial assurance requirements could materially affect our business, the results of our operations and our financial condition.

We ceased paying cash dividends in fiscal 2024; any future cash dividends will be at the discretion of our board of directors and other factors.

On April 22, 2024, the Board of Directors determined not to declare dividends for the foreseeable future in order to align our capital allocation priorities with our corporate focus on accelerating cash flow generation and debt reduction. The payment of any future dividends will be at the discretion of the Board of Directors and will depend upon our financial condition, results of operations, capital requirements, legal requirements, restrictions in our debt agreements and other factors deemed relevant by our Board of Directors. Although our operations are conducted through our subsidiaries, none of our subsidiaries is obligated to make funds available to pay dividends on our common stock. Accordingly, our ability to pay dividends to our stockholders is dependent on the earnings and the distribution of funds from our subsidiaries. Certain agreements governing our indebtedness contain limitations on our ability to pay dividends (including regular annual dividends), as described under “— The agreements governing our indebtedness impose restrictions that may limit our ability to operate our business or require accelerated debt payments .” We cannot provide assurances that the agreements governing our current and future indebtedness will permit us to pay dividends on our common stock.

Legal, Regulatory and Compliance Risks

Our operations depend on our rights and governmental authorizations to mine and operate our properties.

We hold numerous environmental and mineral extraction permits, water rights and other permits, licenses and approvals from governmental authorities authorizing operations at each of our facilities. A decision by a governmental agency to revoke, substantially modify, deny or delay renewal of or apply conditions to an existing permit, license or approval could have a material adverse effect on our ability to continue operations at the affected facility and result in significant costs. For example, certain indigenous groups have challenged the Canadian government’s ownership of the land under which our Goderich mine is operated. There can be no assurances that the Canadian government’s ownership will be upheld or that our existing mining and operating permits will not be revoked or otherwise affected. In addition, although we do not engage in fracking, laws and regulations targeting fracking could lead to increased permit requirements and compliance costs for non-fracking operations, including our salt operations, which require permitted wastewater disposal wells. Rulemaking implementing Utah House Bill 513 (now codified as amended Utah Code §65A-6-4) may adversely impact mineral extraction on the Great Salt Lake, including our existing SOP, sodium chloride and magnesium chloride production. We may be impacted by the Voluntary Agreement we entered into with the Utah Division of FFSL, which outlines brine withdrawal caps based on annual lake elevation, discussed further in Item 1, “Business—Environmental, Health and Safety Matters and Other Regulatory Matters”.

Furthermore, many of our facilities are located on land leased from governmental authorities or third parties. Our leases generally require us to continue mining in order to retain the lease, the loss of which could have a material adverse effect on our ability to continue operations at the affected facility and result in significant costs. In some instances, we have received access rights or easements from third parties which allow for a more efficient operation than would exist without the access or easement. Loss of these access rights or easements could have a material adverse effect on us. In addition, many of our facilities are located near existing and proposed third-party industrial operations that could affect our ability to fully extract, or the manner in which we extract, the mineral deposits to which we have mining rights. For example, certain neighboring operations or land uses may require setbacks that could prevent us from mining portions of our mineral reserves or resources or using certain mining methods.

Expansion of our existing operations or production capacity, or preservation of existing rights in some cases, is also predicated upon securing any necessary permits, licenses and approvals.

Unanticipated litigation or investigations, or negative developments in pending litigation or investigations or with respect to other contingencies, could adversely affect us.

We are currently, and may in the future become, subject to litigation, arbitration or other legal proceedings with other parties. Any claim that is successfully asserted against us in these legal proceedings, or others that could be brought against us in the future, may adversely affect our financial condition, results of operations or prospects. For example, on October 21, 2022 we

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

and certain of our former officers, were named as defendants in a putative securities class action lawsuit filed in the United States District Court for the District of Kansas, alleging that we and such officers made misleading statements damaging shareholders. On July 30, 2025, the court held a hearing at which it approved the settlement of $48.0 million, including fees and expenses awarded to lead counsel and plaintiffs and our insurers have funded the agreed upon settlement. We are also involved periodically in other reviews, inquiries, investigations and other proceedings initiated by or involving government agencies (including litigation brought by Canadian provincial tax authorities as described in Part II, Item 8, Note 8. Income Taxes and Note 18. Subsequent Event of our Consolidated Financial Statements), some of which may result in adverse judgments, settlements, fines, penalties, injunctions or other relief. In these types of matters, it is inherently difficult to determine whether any loss is probable or whether it is possible to estimate the amount of any reasonably possible loss. We cannot predict with certainty if, how or when such proceedings will be resolved or what the eventual judgment, settlement, fine, penalty or other relief, conditions or restrictions, if any, may be. Any eventual judgment, settlement, fine, penalty or other relief, conditions or restrictions could have a material impact on us. For further discussion of pending litigation and governmental proceedings and investigations, see Part II, Item 8, Note 8. Income Taxes, Note 11. Commitments and Contingencies, and Note 18. Subsequent Event of our Consolidated Financial Statements.

We are subject to EHS laws and regulations which could become more stringent and adversely affect our business.

Our operations are subject to an evolving set of federal, state, local and foreign EHS laws and regulations. New or proposed EHS regulatory programs, as well as future interpretations and enforcement of existing EHS laws and regulations, may require modification to our facilities, require substantial increases in equipment and operating costs, subject us to fines, penalties or lead to interruptions, modifications or a termination of operations, which could involve significant capital costs, increases in operating costs or other significant impacts.

For example, we are impacted by the Clean Air Act and other EHS laws and regulations that regulate air emissions. These regulatory programs may subject us to fines or penalties or require us to install expensive emissions abatement equipment, modify our operational practices, obtain additional permits or make other expenditures. Our Ogden facility is located in an area expected to be of continued scrutiny by the Environmental Protection Agency and Utah Division of Air Quality with respect to certain air emissions and related issues under the Clean Air Act.

In addition, if new Clean Water Act regulations are adopted or increased compliance obligations are imposed on existing regulations, we could be adversely affected. For example, a significant portion of our salt products are distributed through salt depots owned and operated by third parties. If these depots are required to adopt more stringent stormwater management practices or are subject to increased compliance requirements under existing Clean Water Act regulations, these depots may pass on any increased costs to us, exit the depot business (requiring us to find new depot partners or establish Company-owned depots) or otherwise cause an adverse impact to our ability to deliver salt to our customers. Additionally, governmental agencies could restrict or limit the use of road salt for highway deicing purposes or adopt laws and regulations to address climate change and greenhouse gases, which could have a material impact on us. See Item 1, “Business—Environmental, Health and Safety and Other Regulatory Matters” for more information about EHS laws and regulations affecting us and their potential impact on us.

We could incur significant environmental liabilities with respect to our current, future or former facilities, adjacent or nearby third-party facilities or off-site disposal locations.

Risks of environmental liabilities is inherent in our current and former operations. At many of our past and present facilities, releases and disposals of regulated substances have occurred and could occur in the future, which could require us to investigate, undertake or pay for remediation activities under CERCLA and other similar EHS laws and regulations. The use, handling, disposal and remediation of hazardous substances currently or formerly used by us, or the liabilities arising from past releases of, or exposure to, hazardous substances may result in future expenditures that could materially and adversely affect our financial results, cash flows or financial condition. Our facilities are also subject to laws and regulations which require us to monitor and detect potential environmental hazards and damages. Our procedures and controls may not be sufficient to timely identify and protect against potential environmental damages and related costs.

We record accruals for contingent environmental liabilities when we believe it is probable that we will be responsible, in whole or in part, for environmental investigation, asset retirement obligation or remediation activities and the expenditures for these activities are reasonably estimable. However, the extent and costs of any environmental investigation, asset retirement obligation or remediation activities are inherently uncertain and difficult to estimate and could exceed our expectations, which could materially affect our financial condition and operating results.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Additionally, we previously sold a portion of our UK salt mine to a third party, which operates a waste management business. The third party’s business, under governmental permits, is allowed to securely dispose certain hazardous waste at the property they own and they pay us fees for engaging in this activity.

Compliance with import and export requirements, the FCPA and other applicable anti-corruption laws may increase the cost of doing business.

Our operations and activities inside and outside the U.S., as well as the shipment of our products across international borders, require us to comply with a number of federal, state, local and foreign laws and regulations, which are complex and increase our cost of doing business. These laws and regulations include import and export requirements, economic sanctions laws, customs laws, tax laws and anti-corruption laws, such as the FCPA, the UK Bribery Act and the Canadian Corruption of Foreign Public Officials Act. We cannot predict how these or other laws or their interpretation, administration and enforcement will change over time. There can be no assurance that our employees, contractors, agents, distributors, customers, payment parties or third parties working on our behalf will not take actions in violation of these laws. Any violations of these laws could subject us to civil or criminal penalties, including fines or prohibitions on our ability to offer our products in one or more countries, debarment from government contracts (and termination of existing contracts) and could also materially damage our reputation, brand, international expansion efforts, business and operating results. In addition, changes to trade or anti-corruption laws and regulations could affect our operating practices or impose liability on us in a manner that could materially and adversely affect our business, financial condition and results of operations.

We are subject to costs and risk associated with a complex regulatory, compliance and legal environment, and we may be adversely affected by changes in laws, industry standards and regulatory requirements.

Our global business is subject to complex requirements of federal, state, local and foreign laws, regulations, treaties and regulatory authorities as well as industry standard-setting authorities. These requirements are subject to change. Changes in the standards and requirements imposed by these laws, regulations, treaties and authorities or adoption of any new laws, regulations or treaties could negatively affect our ability to serve our customers or our business. In the event that we are unable to meet any existing, new or modified standards when adopted, our business could be adversely affected. Some of the federal, state, local and foreign laws and regulations that affect us include those relating to EHS matters; taxes; antitrust and anti-competition laws; data protection and privacy; advertisement and marketing; labor and employment; import, export and anti-corruption; product liability; product registrations and labeling requirements; and intellectual property. We could be adversely affected by the adoption of global minimum taxes as countries implement the Organization for Economic Co-operation and Development’s (“OECD”) Pillar II regime or the side-by-side global minimum tax framework conceptually agreed to amongst the G-7 countries in late June 2025.

If significant import duties were imposed on the salt we import into the U.S. from our Goderich mine, or if we were unable to include the transfer price of such salt in the cost of goods sold for U.S. tax purposes, our financial condition and operating results would be materially and adversely affected. We could also be adversely impacted by changes in tariffs imposed by countries or other trade protection measures, which could decrease our sales in markets where we sell our products. Certain U.S. states have either enacted or proposed legislation that would provide a preference for their agencies or municipalities to use salt mined in the U.S., their home state or selected states. If such legislation is adopted, it could adversely impact the amount of salt sales contracts awarded to us for salt supplied from our Goderich or Cote Blanche mines in the applicable state. Failure to comply with applicable laws, regulations or treaties or to comply with any of contracts we have with governmental entities could preclude us from conducting business with governmental entities and lead to penalties, injunctions, civil remedies or fines.

We may face significant product liability claims and product recalls, which could harm our business and reputation.

We face exposure to product liability and other claims if our products cause harm, are alleged to have caused harm or have the potential to cause harm to consumers or their property. In addition, our products or products manufactured by our customers using our products could be subject to a product recall as a result of product contamination, our failure to meet product specifications or other causes. For example, our customers use our food-grade salt products in food items they produce, such as cheese and bread, which could be subject to a product recall if our products are contaminated or adulterated. For example, see Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Product Recall”. Similarly, the use and application of our animal feed and plant nutrition products could result in a product recall if it were alleged that they were contaminated.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

A product recall could result in significant losses due to the costs of a recall, the destruction of product inventory and production delays to identify the underlying cause of the recall. We could be held liable for costs related to our customers’ product recall if our products cause the recall or other product liability claims if our products cause harm to our customers or their property. Additionally, a significant product liability case, product recall or failure to meet product specifications could result in adverse publicity, harm to our brand and reputation and significant costs, which could have a material adverse effect on our business and financial performance. Our insurance coverage may be insufficient to cover all losses related to product liability claims and product recalls.

Our intellectual property may be misappropriated or subject to claims of infringement.

Intellectual property rights, including patents, trademarks, and trade secrets, are a valuable aspect of our business. We attempt to protect our intellectual property rights primarily through a combination of patent, trademark, and trade secret protection. The patent rights that we obtain may not provide meaningful protection to prevent others from selling competitive products or using similar production processes.

We also rely on trade secret protection to guard confidential unpatented technology, manufacturing expertise, and technological innovation. Although we generally enter into confidentiality agreements with our employees, third-party consultants and advisors to protect our trade secrets, we cannot guarantee that these agreements provide meaningful protection or that adequate remedies will be available in the event of an unauthorized use or disclosure of our trade secrets.

Our brand names and the goodwill associated therewith are an important part of our business. We seek to register our brand names as trademarks where it makes business sense. Our trademark registrations may not prevent our competitors from using similar brand names. Many of our brand names are registered as trademarks in the U.S. and foreign countries. The laws in certain foreign countries in which we do business do not protect trademark rights to the same extent as U.S. law. As a result, these factors could weaken our competitive advantage with respect to our products, services and brands in foreign jurisdictions, which could adversely affect our financial performance.

Strategic and Other Business Risks

We may not successfully implement our strategies.

Our success depends, to a significant extent, on successful implementation of our business strategies, including our back-to-basics strategy, cost savings initiatives, our continuous improvement initiatives, and any other strategies described in the “Business” section of this Form 10-K. We cannot assure that we will be able to successfully implement our strategies or, if successfully implemented, we may not realize the expected benefits of our strategies.

Although we make investments in product innovation, we cannot be certain that we will be able to develop, obtain or successfully implement new products or technologies on a timely basis or that they will be well-received by our customers. Moreover, our investments in new products and technologies involve certain risks and uncertainties and could disrupt our ongoing business. New investments may not generate sufficient revenue, may incur unanticipated liabilities and may divert our limited resources and distract management from our current operations. We cannot be certain that our ongoing investments in new products and technologies will be successful, will meet our expectations and will not adversely affect our reputation, financial condition and operating results.

Our business is dependent upon personnel, including highly skilled personnel. A labor shortage or the loss of key personnel may have a material adverse effect on our performance.

Our business is dependent on our ability to attract, develop and retain personnel. We may encounter difficulty recruiting sufficient numbers of personnel at acceptable wage and benefit levels due to the competitive labor market. If we are unable to attract, develop and retain the personnel necessary for the efficient operation of our business, this could result in higher costs and decreased productivity and efficiency, which may have a material adverse effect on our performance.

Our business is also dependent on the ability to attract, develop and retain highly skilled personnel. An inability to attract, develop and retain personnel with the necessary skills and experience could result in decreased productivity and efficiency, higher costs, the use of less-qualified personnel and reputational harm, which may have a material adverse effect on our performance.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

To help attract, retain and motivate qualified personnel, we offer a compensation package, which may include benefits, short-term incentives, such as annual bonus programs, and long-term incentives, such as stock awards. If our Total Rewards compensation package ceases to be viewed as competitive, for example, the value of long-term awards declines in value as measured by our common stock price, our ability to attract, retain and motivate personnel could be weakened, which could harm our business.

The loss of certain key employees could result in the loss of vital institutional knowledge, experience and expertise, damage critical customer relationships and impact our ability to successfully operate our business and execute our business strategy. We may not be able to find qualified replacements for these key positions and the integration of replacements may be disruptive to our business. In addition, the loss of our key employees who have in-depth knowledge of our mining, manufacturing, engineering processes could lead to increased competition to the extent that those employees are hired by a competitor and are able to recreate our processes or share our confidential information.

If our computer systems, information technology or operations technology are disrupted or compromised, our ability to conduct our business will be adversely impacted.

We rely on computer systems, information technology and operations technology to conduct our business, including cash management, order entry, invoicing, plant operations, vendor payments, recordkeeping of payroll and human resource information, inventory and asset management, shipping of products, and communication with employees and customers. We also use our systems to analyze and communicate our operating results and other data to internal and external recipients. While we maintain some of our critical computer and information technology systems, we are also dependent on third parties to provide important computer and information technology services. We continue to make updates and improvements to our enterprise resource planning system, network and other core applications, which could impact substantially all of our key processes. Any implementation issues could have adverse effects on our ability to properly capture, process and report financial transactions, distribute our products, invoice and collect from our customers and pay our vendors and could lead to increased expenditures or operational disruptions.

We are susceptible to cyber-attacks, computer viruses and other technological disruptions, which generally continue to increase due to evolving threats and our information technology footprint. Attackers are also becoming more sophisticated, including due to the increased availability of artificial intelligence (“AI”) tools, and additional vulnerabilities may be introduced from the use of AI by us, our customers or third parties. We have experienced attempts by unauthorized agents to gain access to our computer systems through the internet, e-mail and other access points. To date, none have resulted in any material adverse impact to our business or operations. While we have programs, policies and procedures in place to identify, prevent and detect any unauthorized access, this does not guarantee that we will be able to detect or prevent unauthorized access to our computer systems. In addition, remote work arrangements for our employees could strain our technology resources and introduce operational risks, including heightened cybersecurity risk. Remote working environments may be less secure and more susceptible to hacking attacks, including phishing and other social engineering attempts. These risks have also impacted, and may in the future impact the third parties on which we rely, and security measures employed by these third parties may also prove to be ineffective at countering threats.

A material failure or interruption of access to our computer systems for an extended period of time or the loss of confidential or proprietary data could adversely affect our operations, reputation and regulatory compliance. While we have mitigation and data recovery plans in place, it is possible that significant expenditures, capital investments and time may be required to correct any of these issues. Additional capital investment and expenditures needed to address, prevent, correct or respond to any of these issues may negatively impact our business, financial condition and results of operations.

Climate change and related laws and regulations could adversely affect us.

The potential impact of climate change on our resources, operations, product demand and the needs of our customers remains uncertain. Scientists have proposed that the physical impacts of climate change could include changes in rainfall patterns, water shortages, changing sea levels, changes to the water levels of lakes and other bodies of water, changing storm patterns and intensities and changing temperature levels. These changes could be severe and vary by geographic location. These changes could negatively impact customer demand for our products as well as our costs and ability to produce and distribute our products. For example, prolonged period of mild winter weather could reduce the market for deicing products. Drought conditions could similarly impact demand for our plant nutrition products. Climate change could also lead to disruptions in the production or distribution of our products due to major storm events or prolonged adverse conditions, changing temperature levels, lake or river level fluctuations or flooding from sea level changes. See “—The results of our operations are dependent on

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

and vary due to weather conditions. Additionally, adverse weather conditions or significant changes in weather patterns could adversely affect us.” for more information.

In addition, transition risks could include legislative and regulatory measures to address climate change and greenhouse gas emissions (including carbon or emissions taxes) have been enacted and are also in various phases of consideration at both the state and federal level, as well as internationally. These measures could restrict our operations, require us to make capital expenditures to be compliant with these initiatives, increase our costs, impact our ability to compete or negatively impact efforts to obtain permits, licenses and other approvals for existing and new facilities. These measures could also result in increased cost of fuel and other consumables used in our operations or in transporting our products. Our inability to timely respond to the risks posed by climate change and the costs of compliance with climate change laws and regulations could have a material impact on us.

We may not be able to expand our business through acquisitions and investments, and acquisitions and investments may not perform as expected. We may not successfully integrate acquired businesses and anticipated benefits may not be realized.

In the future, our business strategy may include supplementing organic growth with acquisitions of and investments in complementary businesses. We may not have acquisition or investment opportunities because we are not able to identify suitable businesses to acquire or invest in, competition with other potential buyers and investors, an inability to obtain suitable financing for an acquisition or investment and restrictions under competition and regulatory laws. If we cannot make acquisitions or investments, our business growth may be limited.

Acquisitions of new businesses and investments in businesses may not perform as expected, may lose value, may not positively impact our financial performance and could increase our debt obligations. Acquisitions and investments involve significant risks and uncertainties, including diversion of management attention, greater than expected liabilities and expenses, inadequate return on capital and unidentified issues not discovered in our due diligence.

The success of any acquisition will also depend on our ability to successfully combine and integrate the acquired business. We may fail to integrate acquired businesses in a timely and efficient manner. The integration process could result in the loss of key employees, higher than expected costs, ongoing diversion of management attention from other strategic opportunities or operational matters, the disruption of our ongoing businesses or increased risk that our internal controls are found to be ineffective.

ITEM 7.    MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The statements in this discussion regarding the industry outlook, our expectations for the future performance of our business, and the other non-historical statements in this discussion are forward-looking statements. These forward-looking statements are subject to numerous risks and uncertainties, including, but not limited to, the risks and uncertainties described in Item 1A, “Risk Factors.” You should read the following discussion together with Item 1A, “Risk Factors” and the Consolidated Financial Statements and Notes thereto included elsewhere in this Form 10-K.

COMPANY OVERVIEW

Compass Minerals is a leading global provider of essential minerals, including salt, consisting of sodium chloride and magnesium chloride and sulfate of potash (SOP”) specialty fertilizer. As of September 30, 2025, we operate 12 production and packaging facilities with more than 1,800 personnel throughout the U.S., Canada and the UK, including:

• The largest rock salt mine in the world in Goderich, Ontario, Canada;

• The largest dedicated rock salt mine in the UK in Winsford, Cheshire;

• A solar evaporation facility located near Ogden, Utah, which is both the largest sulfate of potash specialty fertilizer production site and the largest solar salt production site in the Western Hemisphere; and

• Several mechanical evaporation facilities producing consumer and industrial salt.

Our Salt segment provides highway deicing salt to customers in North America and the UK as well as consumer deicing and water conditioning products, ingredients used in consumer and commercial food preparation, and other salt-based products for consumer, industrial, chemical and agricultural applications in North America. In the UK, we operate a records management business utilizing excavated areas of our Winsford salt mine with one other location in London, England.

Our Plant Nutrition segment produces and markets SOP products in various grades worldwide to distributors and retailers of crop inputs, as well as growers and for industrial uses. We market our SOP under the trade name Protassium+.

Debt Refinancing . In June 2025, we issued $650.0 million aggregate principal amount of our 8.00% Senior Notes due 2030 in a private offering (the “2030 Notes”). We used the net proceeds from the 2030 Notes to (i) repay all outstanding amounts under our senior secured credit facility, including $43.5 million under the revolving credit facility and $191.3 million under our term loan, (ii) redeem approximately $350.0 million of our outstanding 6.75% Senior Notes due 2027, (iii) pay transaction-related fees and expenses, (iv) increase cash on our balance sheet, and (v) for general corporate purposes. The redemption resulted in a loss on debt extinguishment of $7.6 million, which is included in Loss on extinguishment of debt in the Consolidated Statements of Operations for the fiscal year ended September 30, 2025. See the Liquidity and Capital Resources section below and Item 8, Note 10. Long Term Debt and Finance Lease Liabilities of our Consolidated Financial Statements for additional information.

Fortress Exit . In May 2023, we completed the purchase of Fortress North America, LLC (“Fortress), a fire retardant company working to develop long-term aerial and ground fire retardant products to help combat wildfires. In March 2025, we took measures to align our cost structure to our current business needs as part of a larger strategic refocus to improve the profitability of our core Salt and Plant Nutrition businesses, including the process of exiting the Fortress business and terminating the employment of all Fortress employees. As a result of impairment tests performed during fiscal year ended September 30, 2025, we recorded a $53.0 million loss on impairment of long-lived assets related to customer relationships and trade name and a $0.7 million impairment related to the remaining Fortress property, plant and equipment. See Item 8, Note 2. Summary of Significant Accounting Policies of our Consolidated Financial Statements for additional information.

We continue to monitor the effects of the tariffs imposed by the U.S. administration during 2025, the reciprocal tariffs and retaliatory tariffs imposed by other countries, and the impact on our business. Our salt and fertilizer production in Canada is qualified under the United States-Mexico-Canada (“USMCA”) trade agreement. Accordingly, our exports from Canada into the United States are exempt from tariffs at this time.

On July 4, 2025, the U.S. enacted a budget reconciliation package known as the “One Big Beautiful Bill Act of 2025” (“OBBBA”), which includes both tax and non-tax provisions. We are evaluating the effects of these changes and other provisions of this legislation on our consolidated financial statements; however, we do not expect the changes resulting from the tax provisions in OBBBA will have a material impact on the Company’s results of operations due to the timing of our fiscal year reporting.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

RESULTS OF OPERATIONS—For the Fiscal Year September 30, 2025, Compared to the Fiscal Year September 30, 2024

CONSOLIDATED RESULTS OF OPERATIONS

CONSOLIDATED RESULTS COMMENTARY: — For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

• Total sales increased 11.3%, or $126.5 million, due to higher Salt and Plant Nutrition segment sales, partially offset by lower Fortress fire retardant sales. The increase in Salt sales was primarily driven by higher sales volumes, partially offset by lower combined average sales prices. The increase in Plant Nutrition sales, in comparison to the prior fiscal year, primarily reflects higher sales volumes, partially offset by lower average sales price. The results of operations of Fortress included sales of $14.7 million for the fiscal year ended September 30, 2024 and no sales in fiscal 2025. On May 30, 2025, we completed the sale of the Fortress fire retardant assets.

• Operating income was $25.3 million for the fiscal year ended September 30, 2025, compared to an operating loss of $(116.8) million, for the fiscal year ended September 30, 2024. The improvement in operating income for fiscal 2025, compared to the operating loss for fiscal 2024, was primarily due to a decrease in impairment losses and lower selling, general and administrative expenses. These positive effects were partially offset by a decline in gross profit (see Gross Profit and Gross Margin Commentary below) and a decrease in the gain contingent consideration related to the Fortress acquisition.

• Diluted net loss per share of $1.91 improved by $3.08 from a net loss of $4.99 per common share in the prior fiscal year period.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

GROSS PROFIT & GROSS MARGIN COMMENTARY: — For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

Gross Profit: Decreased 2.2%, or $4.3 million; Gross Margin decreased 2.2% from 17.5% to 15.3%

• Salt segment gross profit decreased $18.9 million, primarily due to lower average combined sales prices and higher per-unit product costs, partially offset by higher sales volumes (see Salt operating results).

• Gross profit for the Plant Nutrition segment increased $23.1 million due to higher sales volumes and lower per-unit product costs, partially offset by lower average sales prices and higher per-unit distribution costs (see Plant Nutrition operating results).

• Gross profit was also unfavorably impacted by a reduction in Fortress gross profit, in comparison to the prior year. No Fortress sales occurred in fiscal 2025, and on May 30, 2025, we completed the sale of the Fortress fire retardant assets.

OTHER EXPENSES AND INCOME COMMENTARY: — For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

SG&A: Decreased $24.5 million; Decreased 3.2 percentage points as a percentage of sales from 12.3% to 9.1%

• The decrease in SG&A expense was primarily due to reductions in corporate compensation expense and professional services.

Loss on Impairments: Decreased $137.3 million to $53.7 million

• We recorded a loss on impairment of definite-lived intangible assets and long-lived assets of $53.7 million, during the fiscal year ended September 30, 2025, related to the exit of Fortress.

• During the fiscal year ended September 30, 2024, we recognized goodwill impairments of $51.0 million related to our Plant Nutrition segment and $32.0 million related to our Fortress operations (within the Corporate and Other segment). The Plant Nutrition impairment was primarily the result of reduced cash flow assumptions impacting expected profitability of the Plant Nutrition segment. The Fortress impairment was primarily related to uncertainty surrounding our magnesium chloride-based fire retardants which impacted projected future revenues and cash flows. Also, during the fiscal year ended September 30, 2024, we recorded a loss on impairment of definite-lived intangible asset of $15.6 million, related to Fortress magnesium chloride-based products.

• We recorded a loss on impairment of long-lived assets of $74.8 million for the fiscal year ended September 30, 2024 related to the termination of the lithium development.

• We recorded an impairment loss of $17.6 million for the fiscal year ended September 30, 2024 in our Plant Nutrition segment related to water rights definite-lived intangible asset.

• See Item 8, Note 2. Summary of Significant Policies of our Consolidated Financial Statements for additional information on the impairment losses discussed above.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Other Operating (Income) Expense: Decreased $15.4 million from income of $17.0 million to income of $1.6 million

• The decrease in other operating income was primarily due to a decrease in the gain contingent consideration of $14.2 million related to the Fortress acquisition, along with an increase in legal fees and product recall costs, partially offset by the decrease in severance costs and corporate restructuring charges.

Interest Income: Increased $0.3 million to $1.3 million

• The increase in interest income during the current fiscal year period is primarily due to a higher average cash balance in the current year.

Interest Expense: Decreased $1.0 million to $68.5 million

• The decrease was primarily due to lower debt levels in the current fiscal year period.

Gain (Loss) on Foreign Exchange: Changed by $0.8 million from a $0.7 million loss in the prior fiscal year to $0.1 million gain

• We realized a foreign exchange gain of $0.1 million for the fiscal year ended September 30, 2025, compared to a loss of $0.7 million in the prior year, primarily reflecting the translation of our intercompany loans from Canadian dollars to U.S. dollars.

Loss on Extinguishment of Debt: $7.6 million in the current fiscal year

• We recorded a loss on extinguishment of debt of $7.6 million in the fiscal year ended September 30, 2025, comprised of a $3.9 million prepayment premium related to the partial redemption of 6.75% Senior Notes due 2027 (the “2027 Notes”) and a $3.7 million write-off of unamortized deferred financing costs related to the partial redemption of 2027 Notes and repayment of our term loan. See Item 8, Note 10. Long-Term Debt and Finance Lease Liabilities of our Consolidated Financial Statements for additional information.

Other Expense, Net: Increased $2.1 million to $4.3 million

• The increase is primarily due to fees paid and the write-off of previously capitalized deferred financing costs when we modified our Credit Agreement and entered into the fourth amendment to our Credit Agreement in the current fiscal year.

Income Tax Expense: Increased $8.2 million from $17.9 million to $26.1 million

• The increase in income tax expense was primarily driven by the increase in foreign book income in the fiscal year ended September 30, 2025, compared to the fiscal year ended September 30, 2024. Additionally, the majority of the impairments recorded in the fiscal year ended September 30, 2025 and September 30, 2024 were either not tax deductible or the tax benefit was offset by tax expense for a valuation allowance on the related deferred tax asset.

• Our effective tax rate of (49%) for the fiscal year ended September 30, 2025 is primarily driven by the income mix by country with income recognized in foreign jurisdictions offset by losses recognized in the U.S., for which a valuation allowance has been recorded against the U.S. tax benefit carryforward. Additionally, the majority of the impairments recorded in the fiscal year ended September 30, 2025 and September 30, 2024 were either not tax deductible or the tax benefit was offset by tax expense for a valuation allowance on the related deferred tax asset. See Item 8, Note 8. Income Taxes of our Consolidated Financial Statements for additional information.

• Our income tax provision for the fiscal years ended September 30, 2025 and September 30, 2024 differs from the U.S. statutory rate primarily due to U.S. statutory depletion, state income taxes, nondeductible executive compensation, foreign income, mining and withholding taxes and valuation allowance expense.

OPERATING SEGMENT PERFORMANCE: — For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

The following financial results represent consolidated financial information with respect to sales from our Salt and Plant Nutrition segments for the fiscal years ended September 30, 2025 and September 30, 2024. Sales primarily include revenue from the sales of our products, or “product sales,” and the impact of shipping and handling costs incurred to deliver our salt and plant nutrition products to our customers.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

The Fortress results of operations include sales of $0.0 million and $14.7 million for the fiscal years ended September 30, 2025 and September 30, 2024, respectively. The results of operations of the consolidated records management business and other incidental revenues include sales of $15.1 million and $13.9 million, for the fiscal years ended September 30, 2025 and September 30, 2024, respectively. These sales are not material to our consolidated financial results and are not included in the following operating segment financial data.

SALT SEGMENT RESULTS

Fiscal Year Ended

September 30,

September 30,

Salt Sales (in millions)

Salt Operating Income (in millions)

Salt Sales Volumes (thousands of tons)

Highway deicing

Consumer and industrial

Total tons sold

Average Salt Sales Price (per ton)

Highway deicing

Consumer and industrial

Combined

SALT SEGMENT RESULTS COMMENTARY: — For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

• Salt sales of $1,022.5 million increased $114.7 million, or 12.6%, in the current year reflecting higher sales volumes, partially offset by lower highway deicing average sales prices.

• Salt sales volumes increased 16.5%, increasing sales by approximately $113.7 million. Highway deicing sales volumes increased 20.4% reflecting a more normal winter weather in the North American deicing season, compared to the same period of the prior year. Consumer and industrial sales volumes increased 0.6%, primarily due to higher consumer deicing volumes.

• Combined average sales price decreased 3.3%, partially offsetting the volume increase by approximately $1.0 million driven by a decrease in highway average sales prices.

• Highway deicing average sales prices decreased 2.3% and Consumer and industrial average sales prices increased 4.5%, which resulted in a combined average sales price decrease of 3.3%, compared to the prior year. The lower combined average sales prices are also reflective of sales mix.

• Salt operating income decreased 10.8%, or $17.7 million, due primarily to lower combined average sales prices and higher per-unit product costs, partially offset by higher sales volumes and lower per-unit distribution costs.

PLANT NUTRITION RESULTS

Fiscal Year Ended

September 30,

September 30,

Plant Nutrition Sales (in millions)

Plant Nutrition Operating (Loss) Income (in millions)

Plant Nutrition Sales Volumes (thousands of tons)

Plant Nutrition Average Sales Price (per ton)

PLANT NUTRITION RESULTS COMMENTARY: — For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

• Plant Nutrition sales increased 14.0%, or $25.3 million, due to higher sales volumes, partially offset by lower average

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

sales prices.

• Plant Nutrition sales volumes increased 19.4%, or 53,000 tons, which resulted in a $35.1 million increase in sales driven by positive production trends in 2025 that have allowed us to pursue business beyond normally serviced markets.

• Plant Nutrition average sales prices decreased 4.4%, partially offsetting the increase in sales volume by $9.8 million.

• Plant Nutrition operating income in fiscal year 2025 was $6.5 million, compared to an operating loss of $86.4 million in fiscal year 2024. The improvement in earnings was due to higher sales volumes combined with the prior year including $68.6 million loss from impairments (goodwill and water rights), partially offset by lower average sales prices and higher per-unit distribution costs.

Results of Operations—For the Fiscal Year September 30, 2024, Compared to the Fiscal Year September 30, 2023

For a discussion and analysis of the fiscal year ended September 30, 2024, compared to the fiscal year ended September 30, 2023, see “Part II, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations” of our Form 10-K for the fiscal year ended September 30, 2024, filed with the SEC on December 16, 2024, which is incorporated herein by reference.

Liquidity and Capital Resources—For the Fiscal Year Ended September 30, 2025, Compared to the Fiscal Year Ended September 30, 2024

Historically, our cash flows from operating activities have generally been adequate to fund our basic operating requirements, ongoing debt service and sustaining investment in our property, plant and equipment. We have also used cash generated from operations to fund capital expenditures, pay dividends, fund smaller acquisitions and repay our debt. To a certain extent, our ability to meet our short- and long-term liquidity and capital needs is subject to general economic, financial, competitive and weather conditions, effects of climate change, geological variations in our mine deposits and other factors that are beyond our control. Historically, our working capital requirements have been the highest in the first fiscal quarter (ending December 31) and lowest in the third fiscal quarter (ending June 30). When needed, we may fund short-term working capital requirements by accessing our $325 million revolving credit facility and our revolving AR Securitization Facility extending to March 2027 with a capacity, which is subject to certain conditions, of up to $100.0 million. As of September 30, 2025, we had liquidity of approximately $364.6 million, comprised of $59.7 million of cash and cash equivalents and $304.9 million of availability under our $325 million revolving credit facility.

Principally due to the nature of our deicing business, our cash flows from operations have historically been seasonal, with the majority of our cash flows from operations generated during the first half of the calendar year (see “—Seasonality” for more information). Our working capital needs are heavily impacted by the severity and timing of the winter weather, which generally occurs from December through March each year. Customers tend to replenish their inventory prior to the start of the winter season and following snow events, consequently the number and timing of snow events during the winter season will impact the amount of our accounts receivable and inventory at the end of each quarter. When we have not been able to meet our short-term liquidity or capital needs with cash from operations, whether as a result of the seasonality of our business or other causes, we have met those needs with borrowings under our revolving credit facility. We expect to meet the ongoing requirements for debt service, any declared dividends and capital expenditures from these sources. This, to a certain extent, is subject to general economic, financial, competitive, legislative, regulatory and other factors that are beyond our control.

We manage our capital allocation considering our long-term strategic objectives, required spending to sustain our business and focus on generating adequate returns on capital. On April 22, 2024, the Board of Directors determined not to declare dividends for the foreseeable future in order to align our capital allocation priorities with our corporate focus on accelerating cash flow generation and debt reduction. While our equipment and facilities are generally not impacted by rapid technology changes, our operations require refurbishments and replacements to maintain structural integrity and reliable production and shipping capabilities. When possible, we incorporate efficiency, environmental and safety improvements into our routine capital projects and we plan the timing of larger projects to balance with our liquidity and capital resources. Changes in our operating cash flows may affect our future capital allocation and spending.

We have been able to manage our cash flows generated and used across Compass Minerals to indefinitely reinvest earnings in our foreign jurisdictions or efficiently repatriate those funds to the U.S. As of September 30, 2025, we had $23.6 million of cash and cash equivalents (in our Consolidated Balance Sheets) that was either held directly or indirectly by foreign subsidiaries. In fiscal 2025 and fiscal 2024, we did not repatriate any unremitted foreign earnings. During the second quarter of fiscal 2025, we revised our permanently reinvested assertion. We are expecting to repatriate approximately $11 million of unremitted foreign

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

earnings from our UK operations on which there was no income tax impact as of September 30, 2025. It is our current intention to continue to reinvest the remaining undistributed earnings of our foreign subsidiaries indefinitely. We review our tax circumstances on a regular basis with the intent of optimizing cash accessibility and minimizing tax expense.

In addition, the amount of permanently reinvested foreign earnings is influenced by, among other things, the profits generated by our foreign subsidiaries and the amount of investment in those same subsidiaries. The profits generated by our U.S. and foreign subsidiaries are impacted by the transfer price charged on the transfer of our products between them. Canadian provincial taxing authorities continue to challenge our transfer prices of certain items. The final resolution of these challenges may not occur for several years. We currently expect the outcome of these matters will not have a material impact on our results of operations. However, it is possible the resolution could materially impact the amount of earnings attributable to our foreign subsidiaries, which could impact the amount of permanently reinvested foreign earnings. See Item 8, Note 8. Income Taxes and Note 18. Subsequent Event of our Consolidated Financial Statements for a discussion regarding our Canadian tax reassessments.

Historical Cash Flows

The table below provides a summary of our sources and uses of cash (in millions):

Fiscal Year Ended

September 30,

September 30,

Net cash flow from operating activities

Net cash flow from investing activities

Net cash flow from financing activities

Effect of exchange rate changes on cash and cash equivalents

Net change in cash and cash equivalents

As of September 30, 2025, we had cash and cash equivalents of $59.7 million, an increase of $39.5 million from September 30, 2024.

Cash Flows from Operating Activities

Net cash provided by operating activities, as reflected in the Consolidated Statements of Cash Flows, were $197.7 million, for the fiscal year ended September 30, 2025, as compared to $14.4 million, for the fiscal year ended September 30, 2024. Throughout the fiscal year ended September 30, 2025, we realized a working capital release of approximately $117 million out of finished goods inventory as part of our back-to-basics strategy of optimizing inventory volumes and associated cash impacts. In addition, the increase in cash flows provided by operating activities for the fiscal year ended September 30, 2025, included increases in accounts payable and accrued expenses, partially offset by increases in receivables.

Cash flows from Investing Activities

Net cash used in investing activities, as reflected in the Consolidated Statements of Cash Flows, were $50.0 million and $116.1 million, during the fiscal years ended September 30, 2025 and September 30, 2024, respectively. Cash outflows from investing activities for capital expenditures during the fiscal years ended September 30, 2025 and September 30, 2024 were $69.7 million and $114.2 million, respectively. The decrease in investing activities for capital expenditures during the fiscal year ended September 30, 2025, was primarily due to the termination of the lithium development project in the prior year. During the fiscal year ended September 30, 2025, we received proceeds from the sale of Fortress assets, net of transaction costs of $19.6 million. We estimate that our cash outflows for capital expenditures will be approximately $90 million to $110 million for the fiscal year ended September 30, 2026.

Cash Flows from Financing Activities

Net cash used in financing activities, as reflected in the Consolidated Statements of Cash Flows, were $108.3 million, for the fiscal year ended September 30, 2025, as compared to net cash provided in financing activities of $83.1 million, for the fiscal year ended September 30, 2024. The decrease in cash flows from financing activities during the fiscal year ended September 30, 2025, compared to September 30, 2024, was primarily due to the principal and redemption premium under our 2027 Notes

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

and repayment of our Revolving Credit Facility and Term Loan, partially offset by borrowings under the issuance of our 2030 Notes and Revolving Credit Facility. The Company paid deferred financing fees of $15.9 million and $2.1 million, during the fiscal years ended September 30, 2025 and September 30, 2024, respectively.

Capital Resources

With regard to our Salt and Plant Nutrition businesses, we believe our ongoing primary sources of liquidity will continue to be cash flow from operations and borrowings under our revolving credit facility. We believe that our current banking syndicate is secure and believe we will have access to our entire revolving credit facility. We expect that ongoing requirements for debt service and sustaining capital expenditures will primarily be funded from these sources.

As of September 30, 2025, we had $845.8 million of outstanding indebtedness consisting of $650.0 million outstanding under our 8.00% Senior Notes due 2030, $150.0 million outstanding under our 6.75% Notes due 2027, and $45.8 million outstanding loans under the AR Securitization Facility. Outstanding letters of credit totaling $20.1 million as of September 30, 2025 further reduced available borrowing capacity under the revolving credit facility to $304.9 million.

We may borrow amounts under the revolving credit facility or enter into additional financing to fund our working capital requirements, potential acquisitions and capital expenditures, and for other general corporate purposes.

Our ability to make scheduled interest and principal payments on our indebtedness, to modify our indebtedness, to fund planned capital expenditures, and to fund acquisitions will depend on our ability to generate cash in the future. This, to a certain extent, is subject to general economic, financial, competitive, legislative, climate-related, regulatory and other factors that are beyond our control. Based on our current level of operations, we believe that cash flow from operations and available cash, together with available borrowings under our revolving credit facility, will be adequate to meet our liquidity needs over the next 12 months.

Our debt service obligations could, under certain circumstances, materially affect our financial condition and prevent us from fulfilling our debt obligations. As a holding company, CMI’s investments in its operating subsidiaries constitute substantially all of its assets. Consequently, our subsidiaries conduct substantially all of our consolidated operating activities and own substantially all of our operating assets. The principal source of the cash needed to pay our obligations is the cash generated from our subsidiaries’ operations and their borrowings. Furthermore, we must remain in compliance with the terms of the 2023 Credit Agreement governing our credit facilities, including the consolidated first lien net leverage ratio and consolidated interest coverage ratio, in order to pay dividends to our stockholders. We must also comply with the terms of our indentures governing our 6.75% Senior Notes due December 2027 and our 8.00% Senior Notes due June 2030, which limit the amount of dividends we can pay to our stockholders.

On June 16, 2025, we issued $650.0 million aggregate principal amount of our 8.00% Senior Notes due 2030 in a private offering, pursuant to an indenture, dated June 16, 2025 (the “2030 Notes”), among us, the subsidiary guarantors named therein and Computershare Trust Company, N.A., as trustee. The 2030 Notes are senior unsecured obligations, with interest payable semi-annually on January 1 and July 1, commencing January 1, 2026. The Notes are guaranteed by certain of our domestic subsidiaries. The 2030 Notes will mature on June 16, 2030. We incurred $13.0 million in deferred financing costs, including arrangement, legal and other fees, and will be amortized to interest expense method over the 5-year term of the 2030 Notes.

We used the net proceeds from the 2030 Notes to (i) repay all outstanding amounts under its senior secured credit facility, including $43.5 million under the revolving credit facility and $191.3 million under our term loan, (ii) redeem approximately $350.0 million of its outstanding 2027 Notes at a redemption price of 101.125% of the principal amount, plus accrued and unpaid interest, (iii) pay transaction-related fees and expenses, (iv) increase cash on its balance sheet, and (v) for general corporate purposes. The redemption, completed on June 17, 2025, resulted in a loss on debt extinguishment of $5.7 million, included in Loss on extinguishment of debt in the Consolidated Statements of Operations for the fiscal year ended September 30, 2025. The loss was comprised of a $3.9 million prepayment premium and a $1.8 million write-off of unamortized deferred financing costs. Following the redemption, $150.0 million of the 2027 Notes remain outstanding and continue to accrue interest, payable semi-annually on June 1 and December 1, with unamortized deferred financing costs of $0.7 million as of September 30, 2025.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

On June 16, 2025, we entered into the fifth amendment to its 2023 Credit Agreement, originally dated April 20, 2016, as amended (the “Amended and Restated 2023 Credit Agreement”). The amendment, among other things, (i) fixed the aggregate revolving commitments at $325.0 million, eliminating the automatic periodic step-downs previously included in the December 12, 2024, amendment to the 2023 Credit Agreement, which had scheduled reductions to $250.0 million by July 1, 2026, (ii) permitted the issuance of the 2030 Notes, with net proceeds used to prepay all outstanding loans under the Existing Amended and Restated Credit Agreement, including $43.5 million outstanding under the revolving credit facility and $191.3 million outstanding under our term loan, plus accrued and unpaid interest, (iii) permitted the Company to utilize certain baskets under covenants restricting the incurrence of indebtedness, liens, investments, dividends, and junior debt prepayments, and (iv) modified the financial maintenance covenants, which are tested on a quarterly basis, as follows: (A) replaced the leverage-based covenant, which previously required compliance with a maximum ratio of consolidated total net indebtedness to consolidated EBITDA of 6.50x (with a step-down to 5.75x on December 31, 2025, and a further step-down to 4.75x on March 31, 2026) with a leverage-based covenant which requires compliance with a maximum ratio of consolidated first lien net indebtedness to consolidated EBITDA of 2.75x (with a step-down to 2.50x on December 31, 2025) and (B) lowered the required minimum ratio of consolidated EBITDA to consolidated interest expense from 2.00x (with a step-up to 2.25x on March 31, 2026) to 1.50x. Consolidated first lien net debt includes the aggregate principal amount of consolidated first lien debt, net of unrestricted cash not to exceed $100.0 million. In connection with the prepayment of our term loan, we recorded a loss on debt extinguishment of $1.9 million, included in Loss on extinguishment of debt on the Consolidated Statements of Operations for the fiscal year ended September 30, 2025, related to the write-off of unamortized deferred financing costs related to this instrument. As of September 30, 2025, our consolidated first lien net leverage ratio was approximately 0.01x.

On December 12, 2024, we entered into the fourth amendment to our 2023 Credit Agreement, which, among other things, eased the restrictions of certain covenants contained in the agreement. The amendment included increasing the maximum allowed consolidated total net leverage ratio (as defined and calculated under the terms of the amended 2023 Credit Agreement) to 6.5x as of the last day of any quarter through the fiscal quarter ended September 30, 2025, then gradually stepping down to 4.5x by the fiscal quarter ended December 31, 2026 and thereafter. The amendment also decreased the Revolving Commitments (as defined in the Existing Credit Agreement) from $375 million to $325 million with additional reductions stepping down to $250 million on July 1, 2026.

On September 18, 2024, we received a notice of default relating to our 6.750% Senior Notes due 2027 because we failed to timely furnish a Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2024. We had 90 days from receipt of the notice to remedy prior to it becoming an Event of Default under the terms of the Indenture, dated November 26, 2019. Our Q3 Form 10-Q was filed with the SEC on October 30, 2024.

On September 13, 2024, we entered into amendments to our 2023 Credit Agreement and our AR Securitization Facility, which extended the deadline for delivery of our financial statements for the quarter ended June 30, 2024, together with the respective compliance certificates, to November 29, 2024, 152 days after the last day of the quarter ended June 30, 2024.

On August 12, 2024, we entered into amendments to our 2023 Credit Agreement and our AR Securitization Facility, which extended the deadline for delivery of our financial statements for the quarter ended June 30, 2024, together with the respective compliance certificates, from 45 days to 75 days after the last day of the quarter ended June 30, 2024.

On May 5, 2023, we entered into an agreement to amend and restate our credit agreement entered into on November 26, 2019 (as in effect prior to such restatement, the “Existing Credit Agreement”) with a new $575 million senior secured credit agreement due May 5, 2028 (as amended, the “2023 Credit Agreement”), comprised of a $375 million revolving credit facility and $200 million term loan. The term loan is payable in quarterly installments of interest and principal, which began September 30, 2023. The 2023 Credit Agreement increases the Applicable Margins by 25 basis points over those defined in the Existing Credit Agreement and adds an additional level at a consolidated total leverage ratio (defined below) of greater than 4.00 to 1.00. Proceeds from the 2023 Credit Agreement were used to redeem our $250 million 4.875% Senior Notes on May 10, 2023 and pay off the Existing Credit Agreement term loan balance of $16.9 million. See Item 8, Note 10. Long Term Debt and Finance Lease Liabilities of our Consolidated Financial Statements for additional details.

On March 27, 2024, we entered into an amendment to our 2023 Credit Agreement, which eased the restrictions of certain covenants contained in the agreement. The amendment included increasing the maximum allowed consolidated total net leverage ratio (as defined and calculated under the terms of the amended 2023 Credit Agreement) to 6.5x as of the last day of any quarter through the fiscal quarter ended December 31, 2024, then gradually stepping down to 4.75x by the fiscal quarter ended March 31, 2026 and thereafter.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

On June 30, 2020, certain of our U.S. subsidiaries entered into a three-year committed revolving accounts receivable financing facility for up to $100.0 million of borrowing with PNC Bank, National Association, as administrative agent and lender, and PNC Capital Markets, LLC, as structuring agent. In January 2023, certain of the Company’s U.S. subsidiaries entered into the second amendment to the AR Securitization Facility with PNC Bank, which temporarily eased the restrictions of certain covenants contained in the agreement through March 2023. The amendment made certain adjustments to the financial tests including: (i) the default ratio and (ii) the delinquency ratio to make compliance with such tests more likely. On March 27, 2024, certain of our U.S. subsidiaries entered into an amendment to its revolving accounts receivable financing facility with PNC Bank, National Association, extending the facility to March 2027. As of September 30, 2025, we had $45.8 million of outstanding loans under this accounts receivable financing facility. See Item 8, Note 10. Long Term Debt and Finance Lease Liabilities of our Consolidated Financial Statements for more information.

We are in compliance with our debt covenants as of September 30, 2025, although we can make no assurance that we will remain in compliance with these ratios. Furthermore, we may need to refinance all or a portion of our indebtedness on or before maturity; however, we cannot provide assurance that we will be able to refinance any of our indebtedness on commercially reasonable terms or at all.

We have various foreign and state net operating loss (“NOL”) carryforwards that may be used to offset a portion of future taxable income to reduce our cash income taxes that would otherwise be payable. However, we may not be able to use any or all of our NOL carryforwards to offset future taxable income and our NOL carryforwards may become subject to additional limitations due to future ownership changes or otherwise. As of September 30, 2025, we had $80.5 million of gross federal NOL carryforwards and $7.1 million of net operating tax-effected state NOL carryforwards that expire beginning in 2031. Also as of September 30, 2025 and September 30, 2024, we had $1.9 million and $2.0 million, respectively, of tax-effected state capital losses which will expire beginning in 2027 and $1.6 million and $1.6 million, respectively, of tax-effected federal capital losses, which will expire beginning in 2025.

Management assesses the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit use of the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred in the U.S. over the three-year period ended September 30, 2025. Such objective evidence limits the ability to consider other subjective evidence, such as our projections for future income. On the basis of this evaluation, during the fiscal year ended September 30, 2025, an additional valuation allowance of $33.1 million has been recorded to recognize only the portion of the U.S. deferred tax assets that are more likely than not to be realized. The amount of the deferred tax assets considered realizable, however, could be adjusted if estimates of future taxable income during the carryforward period are increased or reduced or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as our projections for income.

We have a defined benefit pension plan for certain of our current and former UK employees. Beginning December 1, 2008, future benefits ceased to accrue for the remaining active employee participants in the plan concurrent with the establishment of a defined contribution plan for these employees. Generally, our cash funding policy is to make the minimum annual contributions required by applicable regulations. As of September 30, 2025, the fair value of the plan’s assets are in excess of the accumulated benefit obligations and we expect to be required to use cash from operations above our historical levels to fund the plan in the future.

Contractual Obligations

We believe we have sufficient liquidity to fund our operations and meet both short-term and long-term obligations. Our material future obligations include the contractual obligations and other commitments as described below.

We are party to contractual obligations involving commitments to make payments to third parties. These obligations impact our liquidity and capital resource needs. As of September 30, 2025, we had total future contractual obligations of approximately $1.3 billion, with approximately $127.5 million due during fiscal 2026.

We have a contractual commitment to repay our long-term debt of $845.8 million based on the terms of our debt agreements, of which $0.0 million is payable within the next twelve months. Our interest commitment based on the debt balances at September 30, 2025 is $282.5 million, with $64.3 million expected within the next twelve months. The remainder of our contractual commitments consist of lease payments, purchase obligations and commitments, income taxes and employer pension and benefit plan obligations.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

See Item 8, Note 4. Leases and Note 10. Long Term Debt and Finance Lease Liabilities of our Consolidated Financial Statements for amounts outstanding as of September 30, 2025 related to leases and debt, respectively. Refer to Item 8, Note 11. Commitments and Contingencies and Note 18. Subsequent Event of our Consolidated Financial Statements for amounts related to purchase obligations and performance bonds. Our contractual obligations related to employer pension plan obligations represent the funded status recognized as of September 30, 2025. See Item 8, Note 9. Pension Plans and Other Benefits of our Consolidated Financial Statements for information related to these plans.

In addition, we have other future contingent commitments of approximately $231.6 million, consisting of letters of credit and performance bonds, due during fiscal 2026. At September 30, 2025, we had $211.5 million of outstanding performance bonds, which includes bonds related to Ontario mining tax reassessments, and with the settlement that occurred during the first quarter of fiscal 2026, the bonds posted as collateral for the 2002-2018 period were released. Refer to Item 8, Note 11. Commitments and Contingencies and Note 18. Subsequent Event of our Consolidated Financial Statements for additional details.

Product Recall

On October 25, 2024, we issued a recall for specific production lots of food-grade salt produced at our Goderich Plant following a customer report of a non-organic, foreign material in our product. We subsequently expanded the voluntary recall to include food products from the Goderich Plant between September 18, 2024 and November 6, 2024. We followed recall protocol and notified the BRCGS Global Standard for Food Safety certifying body, the Canadian Food Inspection Agency (“CFIA”) and the U.S. Food and Drug Administration (“FDA”). We completed our investigation and continue to assess the scope and magnitude of customer claims related to the recall. At this time, based on currently available information and our applicable insurance coverage, we do not believe any incremental losses will have a material adverse effect on our results of operations or cash flows in future periods. The recall in the United States, supervised by the FDA, is complete, and the matter is closed with FDA. The CFIA has conducted a follow-up inspection of the Goderich Plan to verify compliance with regulatory requirements and identified no non-compliances. See Item 8, Note 11. Commitments and Contingencies of our Consolidated Financial Statements for additional information.

Off-Balance Sheet Arrangements

At September 30, 2025, we had no off-balance sheet arrangements that have or are likely to have a material current or future effect on our consolidated financial statements.

Liquidity and Capital Resources—For the Fiscal Year Ended September 30, 2024, Compared to the Fiscal Year Ended September 30, 2023

For a comparison of our liquidity and capital resources for the fiscal year ended September 30, 2024, compared to the fiscal year ended September 30, 2023, see “ Part II, Item 7. Management ’ s Discussion and Analysis of Financial Condition and Results of Operations ” of our Form 10-K for the fiscal year ended September 30, 2024, filed with the SEC on December 16, 2024, which is incorporated herein by reference.

Reconciliation of Net Loss to EBITDA and Adjusted EBITDA

Management uses a variety of measures to evaluate our performance. While our consolidated financial statements, taken as a whole, provide an understanding of our overall results of operations, financial condition and cash flows, we analyze components of the consolidated financial statements to identify certain trends and evaluate specific performance areas. In addition to using U.S. GAAP financial measures, such as gross profit, net (loss) income and cash flows generated by operating activities, management uses earnings before interest, taxes, depreciation and amortization (“EBITDA”) adjusted for items management believes are not indicative of our ongoing operating performance (“Adjusted EBITDA”). Both EBITDA and Adjusted EBITDA are non-U.S. GAAP financial measures used to evaluate the operating performance of our core business operations because our resource allocation, financing methods and cost of capital, and income tax positions are managed at a corporate level, apart from the activities of the operating segments, and our operating facilities are located in different taxing jurisdictions, which can cause considerable variation in net earnings. We also use EBITDA and Adjusted EBITDA to assess our operating performance and return on capital against other companies, and to evaluate potential acquisitions or other capital projects. EBITDA and Adjusted EBITDA are not calculated under U.S. GAAP and should not be considered in isolation or as a substitute for net income, cash flows or other financial data prepared in accordance with U.S. GAAP or as a measure of our overall profitability or liquidity.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

EBITDA and Adjusted EBITDA exclude interest expense, income taxes and depreciation and amortization, each of which are an essential element of our cost structure and cannot be eliminated. Furthermore, Adjusted EBITDA excludes other cash and non-cash items, including stock-based compensation, interest income, (gain) loss on foreign exchange, other (income) expense, net and other significant items that management does not consider indicative of normal operations. Other significant items, such as executive transition costs, restructuring charges and impairment charges, involve distinct initiatives that are not reflective of core operating activities and affect the comparability of our operational results across reporting periods. Our borrowings are a significant component of our capital structure and interest expense is a continuing cost of debt. We are also required to pay income taxes, a required and ongoing consequence of our operations. We have a significant investment in capital assets and depreciation and amortization reflect the utilization of those assets in order to generate revenues. Our employees are vital to our operations and we utilize various stock-based awards to compensate and incentivize our employees. Consequently, any measure that excludes these elements has material limitations. While EBITDA and Adjusted EBITDA are frequently used as measures of operating performance, these terms are not necessarily comparable to similarly titled measures of other companies due to the potential inconsistencies in the method of calculation.

Adjusted EBITDA decreased 3.6%, or $7.5 million for the fiscal year ended September 30, 2025, compared to the fiscal year ended September 30, 2024, primarily due to a reduction in gain related to the Fortress contingent consideration of $14.2 million and a reduction in gross profit, partially offset by a decrease in selling, general and administrative expenses. The calculation of EBITDA and Adjusted EBITDA as used by management is set forth in the table below (in millions):

Fiscal Year Ended

September 30,

September 30,

Net loss

Interest expense

Income tax expense

Depreciation, depletion and amortization

EBITDA

Adjustments to EBITDA:

Stock-based compensation - non-cash

Interest income

(Gain) loss on foreign exchange

Loss on extinguishment of debt

Restructuring charges (a)

Total impairment loss (b)

Product recall costs (c)

Other expense, net

Adjusted EBITDA

(a) During the fiscal year ended September 30, 2025, we incurred severance and related charges due to a reduction in workforce. During the fiscal year ended September 30, 2024, we incurred severance and related charges related to reductions in workforce, changes to executive leadership and additional restructuring costs related to the termination of our lithium development project.

(b) During the fiscal year ended September 30, 2025, we recorded a loss on impairment of $53.0 million, related to Fortress intangible assets and $0.7 million, related to Fortress long-lived assets. During the fiscal year ended September 30, 2024, we recorded a loss on impairment of long-lived assets of $74.8 million related to the termination of the lithium development project; goodwill of $32.0 million related to Fortress, long-lived assets of $15.6 million and inventory of $2.4 million related to Fortress; and goodwill of $51.0 million related to Plant Nutrition for the twelve months ended Sept. 30, 2024. Impairments of long-lived assets, intangible assets, and goodwill are included in loss on impairments, while the impairment of inventory is included in product cost, both on the Consolidated Statements of Operations. Refer to Item 8, Note 2. Summary of Significant Accounting Policies and Note 15. Fair Value Measurements of our Consolidated Financial Statements for additional details.

(c) We recorded product recall costs related to a recall for food-grade salt produced at our Goderich Plant. Refer to Item 8, Note 11. Commitments and Contingencies of our Consolidated Financial Statements for additional details.

Our net income, EBITDA and Adjusted EBITDA are impacted by other events or transactions that we believe to be important in understanding our earnings trends such as the variability of weather. The impact of weather has not been adjusted in the amounts presented above. Our fiscal year ended September 30, 2025 results included a more normal winter weather in the North American deicing season, which led to a 20% increase in highway deicing sales volume. Our fiscal year ended September 30, 2024 results were unfavorably impacted by winter weather activity as compared to an average winter in the markets we serve.

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Management’s Discussion of Critical Accounting Estimates

The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the reporting date and the reported amounts of revenue and expenses during the reporting period. Actual results could vary from these estimates. We have identified the critical accounting estimates that we believe are most important to the portrayal of our financial condition and results of operations. The estimates set forth below require significant subjective or complex judgments by management, often as a result of the need to make estimates about the effect of matters that are inherently uncertain.

Intangible Assets . On March 25, 2025, we took measures to align our cost structure to our current business needs as part of a larger strategic refocus to improve the profitability of our core Salt and Plant Nutrition businesses, including the process of exiting the Fortress North America, LLC (“Fortress”) fire retardant business and terminating the employment of all Fortress employees.

As a result of the above items impacting Fortress, we determined that there were indicators of impairment with the associated Fortress intangible assets. Therefore, we tested these intangibles for impairment. As there were no future cash flows expected related to these intangible assets, customer relationships was determined to have a fair value of zero using an income approach under ASC 820, Fair Value Measurement (Level 3 inputs). Consequently, we recorded a loss on impairment of $53.0 million, for the fiscal year ended September 30, 2025.

Additionally, we performed an impairment test on the remaining Fortress asset group (including property, plant and equipment (“PP&E”), inventory and in-process research and development (“IPR&D”), with a carrying amount of $19.7 million. The impairment test under ASC 360, Property, Plant Equipment and Other Assets, compared the asset group’s undiscounted cash flows to its carrying amount. We determined the fair value of the asset group using a market approach under ASC 820, Fair Value Measurement. The fair value of the asset group was based on relevant third-party non-binding offers received for the specific asset group (Level 2 inputs). The asset group (PP&E, inventory and IPR&D) was not impaired as its fair value, based on market indications, approximated or exceeded its carrying value. The fair value estimates involved significant estimates and assumptions, which may differ from actual outcomes. At June 30, 2025, the Company performed an impairment test on the remaining Fortress asset group related to PP&E and recorded a loss on impairment of $0.7 million, during the fiscal year ended September 30, 2025.

Mineral Interests – As of September 30, 2025 and September 30, 2024, we maintained $115.8 million and $117.7 million, respectively, of net mineral properties as a part of property, plant and equipment. Mineral interests include probable mineral reserves. We lease mineral reserves at several of our extraction facilities. These leases have varying terms, and many provide for a royalty payment to the lessor based on a specific amount per ton of mineral extracted or as a percentage of sales.

Mineral interests are primarily depleted on an actual units-of-production method based on a combination of third-party and internal qualified geologists’ estimates of recoverable reserves. Our rights to extract minerals are generally contractually limited by time or lease boundaries. If we are not able to continue to extend lease agreements, as we have in the past, at commercially reasonable terms, without incurring substantial costs or incurring material modifications to the existing lease terms and conditions, if the assigned lives realized are less than those projected by management, or if the actual size, quality or recoverability of the minerals is less than the estimated probable reserves, then the rate of amortization could be increased or the value of the reserves could be reduced by a material amount.

Income Taxes – Developing our provision for income taxes and analyzing our potential tax exposure items requires significant judgment and assumptions as well as a thorough knowledge of the tax laws in various jurisdictions. These estimates and judgments occur in the calculation of certain tax liabilities and in the assessment of the likelihood that we will be able to realize our deferred tax assets, which arise from temporary differences between the tax and financial statement recognition of revenue and expense, carryforwards and other items. Based on all available evidence, both positive and negative, the reliability of that evidence and the extent such evidence can be objectively verified, we determine whether it is more likely than not that all, or a portion of, the deferred tax assets will be realized.

In evaluating our ability to realize our deferred tax assets, we consider the sources and timing of taxable income, our ability to carry back tax attributes to prior periods, qualifying tax planning and estimates of future taxable income exclusive of reversing temporary differences. In determining future taxable income, our assumptions include the amount of pre-tax operating income according to multiple federal, international and state taxing jurisdictions, the origination of future temporary differences and the implementation of feasible and prudent tax planning. These assumptions require significant judgment about material estimates,

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

assumptions and uncertainties in connection with the forecasts of future taxable income, the merits in tax law and assessments regarding previous taxing authorities’ proceedings or written rulings. While these assumptions are consistent with the plans and estimates we use to manage the underlying businesses, differences in our actual operating results or changes in our tax planning, tax credits, tax laws or our assessment of the tax merits of our positions could affect our future assessments.

In addition, the calculation of our tax liabilities involves uncertainties in the application of complex tax regulations in multiple jurisdictions. We recognize potential liabilities in accordance with applicable U.S. GAAP for anticipated tax issues in the U.S. and other tax jurisdictions based on our estimate of whether, and the extent to which, additional taxes will be due. If payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities would result in tax benefits being recognized in the period when we determine the liabilities are no longer necessary. If our estimate of tax liabilities proves to be less than the ultimate assessment, a further charge to expense would result. See Item 8, Note 8. Income Taxes of our Consolidated Financial Statements for further discussion of our income taxes. We have elected to account for GILTI in the year the tax is incurred, rather than recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years.

Other Significant Accounting Estimates – Other significant accounting estimates not involving the same level of measurement uncertainties as those discussed above are nevertheless important to an understanding of our consolidated financial statements. Policies related to revenue recognition, allowance for doubtful accounts, valuation of inventory reserves, equity compensation instruments, legal reserves, derivative instruments, post-employment benefit obligations and environmental accruals require judgments.

Effects of Currency Fluctuations and Inflation

Our operations outside of the U.S. are conducted primarily in Canada and the UK. Therefore, our results of operations are subject to both currency transaction risk and currency translation risk. We incur currency transaction risk whenever we or one of our subsidiaries enter into either a purchase or sales transaction using a currency other than the local currency of the transacting entity. With respect to currency translation risk, our financial condition and results of operations are measured and recorded in the relevant local currency and then translated into U.S. dollars for inclusion in our historical consolidated financial statements. Exchange rates between these currencies and the U.S. dollar have fluctuated significantly from time to time and may do so in the future. The majority of revenues and costs are denominated in U.S. dollars, with Canadian dollars and British pounds sterling also being significant. We generated 28% of our fiscal 2025 sales in foreign currencies, and we incurred 27% of our fiscal 2025 total operating expenses in foreign currencies. Additionally, we have approximately $360 million of net assets denominated in foreign currencies. In fiscal 2025, the average rate for the U.S. dollar strengthened against the Canadian dollar and the British pound sterling. In fiscal 2024, the average rate for the U.S dollar strengthened slightly against the Canadian dollar and weakened against the British pound sterling. In fiscal 2023, the average rate for the U.S. dollar weakened against the Canadian dollar and the British pound sterling. Significant changes in the value of the Canadian dollar or the British pound sterling relative to the U.S. dollar could have a material adverse effect on our financial condition and our ability to meet interest and principal payments on U.S. dollar-denominated debt, including borrowings under our senior secured credit facilities.

Although inflation has not had a significant impact on our operations in the current period, our efforts to recover cost increases due to inflation may be hampered as a result of the competitive industries and countries in which we operate. For more information, see Part I, Item 1A, “Risk Factors”.

Seasonality

We experience a substantial amount of seasonality in our sales, including our salt deicing product sales. Consequently, our Salt segment sales and operating income are generally higher in the first and second fiscal quarters (ending December 31 and March 31) and lower during the third and fourth fiscal quarters of each year (ending June 30 and September 30). In particular, sales of highway and consumer deicing salt and magnesium chloride products vary based on the severity of the winter conditions in areas where the products are used. Following industry practice in North America and the UK, we seek to stockpile sufficient quantities of deicing salt throughout the first, third and fourth fiscal quarters (ending December 31, June 30 and September 30) to meet the estimated requirements for the winter season. Our Plant Nutrition business is also seasonal. As a result, we and our customers generally build inventories during the Plant Nutrition business’ low demand periods of the year (which are typically winter and summer, but can vary due to weather and other factors) to ensure timely product availability during the peak sales seasons (which are typically spring and autumn, but can also vary due to weather and other factors).

2025 FORM 10-K

Table of Contents

COMPASS MINERALS INTERNATIONAL, INC.

Climate Change

The potential impact of climate change on our operations, product demand and the needs of our customers remains uncertain. Significant changes to weather patterns, a reduction in average snowfall or regional drought within our served markets could negatively impact customer demand for our products and our costs, as well as our ability to produce our products. For example, prolonged periods of mild winter weather could reduce the demand for deicing products. Drought or excessive precipitation could similarly impact demand for our SOP products, as well as continue to impact the amount and quality of feedstock used to produce SOP at our Ogden facility due to changes in brine levels, mineral concentrations or other factors, which could have a material impact on our Plant Nutrition results of operations. Climate change could also lead to disruptions in the production or distribution of our products due to major storm events or prolonged adverse conditions, changing temperature levels, lake level fluctuations or flooding from sea level changes. Climate change or governmental initiatives to address climate change may affect our operations and necessitate capital expenditures in the future, although capital expenditures for climate-related projects were not material in fiscal 2025 and are not expected to be material in fiscal 2026. For more information, see Part I, Item 1A, “Risk Factors” and Part I, Item1 “Business—Environmental, Health and Safety and Other Regulatory Matters.”

Significant Accounting Policies and Recent Accounting Pronouncements

See Item 8, Note 2. Summary of Significant Accounting Policies of our Consolidated Financial Statements for a discussion of significant accounting policies and recent accounting pronouncements.