ADVANCED DRAINAGE SYSTEMS, INC.

1. BACKGROUND AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Description of Business -Advanced Drainage Systems, Inc. and subsidiaries (collectively referred to as “ADS” or the “Company”), incorporated in Delaware, designs, manufactures and markets innovative water management solutions in the stormwater and onsite wastewater industries, providing superior drainage solutions for use in the construction and agriculture markets. ADS’s products are used across a broad range of end markets and applications, including non-residential, residential, infrastructure and agriculture applications.

On February 2, 2026, the Company completed the acquisition of National Diversified Sales (“NDS”). NDS expands the Company’s water management offering into complementary products through the addition of NDS’ residential water management, access box and irrigation solutions. See “Note 4. Acquisitions” for additional information.

Following the acquisition of NDS, the Company is managed and reports results of operations intwo reportable segments: Stormwater and Wastewater (formerly Infiltrator).

The Company’s fiscal year begins on April 1 and ends on March 31. Unless otherwise noted, references to “year” pertain to the fiscal year. For example, 2026 refers to fiscal 2026, which is the period from April 1, 2025 to March 31, 2026.

Principles of Consolidation -The consolidated financial statements include the Company, its wholly-owned subsidiaries, its majority owned subsidiaries, and variable interest entities (“VIEs”) of which the Company is the primary beneficiary. The Company uses the equity method of accounting for equity investments where it exercises significant influence but does not hold a controlling financial interest. Such investments are recorded in Other assets in the Consolidated Balance Sheets and the related equity in earnings from these investments are included in Equity in net income of unconsolidated affiliates in the Consolidated Statements of Operations. All intercompany balances and transactions have been eliminated in consolidation.

Presentation -Certain prior period balance sheet captions have been recast to conform with current period presentation.

Estimates -The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingencies and liabilities at the balance sheet date and the reported amounts of revenues and expenses during the reporting period. Significant estimates include, but are not limited to, the allowance for credit losses, valuation of inventory, useful lives of property, plant and equipment and amortizing intangible assets, determination of the proper accounting for leases, valuation of equity method investments, goodwill, intangible assets and other long-lived assets for impairment, accounting for stock-based compensation, determination of allowances for sales returns, rebates and discounts, determination of the valuation allowance, if any, on deferred tax assets, and reserves for uncertain tax positions. Management’s estimates and assumptions are evaluated on an ongoing basis and are based on historical experience, current conditions and available information. Management believes the accounting estimates are appropriate and reasonably determined; however, due to the inherent uncertainties in making these estimates, actual results could differ from those estimates.

Receivables and Allowance for Credit Losses -Receivables include trade receivables, net of an allowance for credit losses, income tax receivable, insurance recoverable and other miscellaneous receivables. Receivables at March 31, 2026 and 2025 are as follows:

The Company extends credit to customers based on an evaluation of their financial condition and collateral is generally not required. The Company records an allowance for credit losses at the time accounts receivable are recorded based on the Company’s historical write-off activity, an evaluation of the current economic environment and the Company’s expectations of future economic conditions.

Inventories -Inventories are stated at the lower of cost or net realizable value. The Company’s inventories are maintained on the first-in, first-out (“FIFO”) method. Costs include the cost of acquiring materials, including in-bound freight from vendors and freight incurred for the transportation of raw materials, tooling or finished goods between the Company’s manufacturing plants and its distribution centers, direct and indirect labor, factory overhead and certain corporate overhead costs related to the production of inventory.

Property, Plant and Equipment and Depreciation Method -Property, plant and equipment are recorded at cost less accumulated depreciation, with the exception of assets acquired through acquisitions, which are initially recorded at fair value. Equipment acquired under finance lease is recorded at the present value of the future minimum lease payments. Depreciation is computed for financial reporting purposes using the straight-line method over the estimated useful lives of the related assets or the lease term, if shorter, as follows:

Costs of additions and major improvements are capitalized, whereas maintenance and repairs that do not improve or extend the life of the asset are charged to expense as incurred. When assets are retired or disposed, the cost and related accumulated depreciation are removed from the asset accounts and any resulting gain or loss is reflected in Loss (gain) on disposal of assets and costs from exit and disposal activities in the Consolidated Statements of Operations. Construction in progress is also recorded at cost and includes capitalized interest, capitalized payroll costs and related costs such as taxes and other fringe benefits.

Goodwill & Intangible Assets -The Company records acquisitions resulting in the consolidation of an enterprise using the acquisition method of accounting. Under this method, the Company records the assets acquired, including intangible assets that can be identified, and liabilities assumed based on their estimated fair values at the date of acquisition. The purchase price in excess of the fair value of the identifiable assets acquired and liabilities assumed is recorded as goodwill.

Goodwill - Goodwill is reviewed annually for impairment during the fourth quarter or whenever events or changes in circumstances indicate the carrying value may be greater than fair value. GAAP allows entities testing goodwill for impairment the option of performing a qualitative assessment before calculating the fair value of a reporting unit for the goodwill impairment test, a quantitative assessment. In fiscal 2026, the Company revised its reportable segments and allocated the goodwill balance to its revised reporting units. For the fiscal year ended March 31, 2026, the Company completed a quantitative fair value assessment for all reporting units. For the fiscal years ended March 31, 2025 and March 31, 2024, the Company completed a qualitative fair value assessment for all reporting units, except for Cultec, for which the Company completed a quantitative analysis. The Company did not incur any impairment charges for goodwill for the periods presented.

Intangible Assets — Definite-Lived -Definite-lived intangible assets are amortized using the straight-line method or an accelerated method over their estimated useful lives and are tested for recoverability whenever events or changes in circumstances indicate that carrying amounts of the asset group may not be recoverable. If the estimated undiscounted future cash flows are less than the carrying amounts of such assets, an impairment loss is recognized to the extent the fair value of the asset less any costs of disposition is less than the carrying amount of the asset. The Company did not incur any impairment charges for Definite-Lived Intangible assets for the periods presented.

Intangible Assets — Indefinite-Lived -Indefinite-lived intangible assets are tested for impairment annually in the fourth quarter or whenever events or changes in circumstances indicate the carrying value may be greater than fair value. GAAP allows entities testing indefinite-lived intangible assets for impairment the option of performing a qualitative assessment before calculating the fair value of the indefinite-lived intangible assets for the impairment test. ADS completed a qualitative fair value assessment of indefinite-lived trademarks as of March 31, 2026, March 31, 2025 and March 31, 2024. The Company didnot incur any impairment charges for Indefinite-Lived Intangible assets for the periods presented.

Held for Sale and Discontinued Operations Classification- Under the accounting guidance contained in Accounting Standards Codification Topic 205, Presentation of Financial Statements (“ASC 205”), businesses that, upon acquisition, meet the held for sale criteria are not analyzed under the strategic shift test. Instead, they are reported in discontinued operations automatically based on their held for sale classification. The strategic shift test does not apply because the acquired businesses were not previously part of the acquirer.

The Company determined Teco S.r.l., Kimplas Piping Systems Private Limited, Kimplas Limited, Teco Irrigation USA, Inc. and Fish Water Products Sdn. Bhd. (collectively, the “NDS International Entities”) met the held for sale criteria upon acquisition. As a result, the assets and liabilities of the NDS International Entities have been classified held for sale and are reported as assets held for sale and liabilities held for sale on the Consolidated Balance Sheet. The results of the NDS International Entities have been accounted for as discontinued operations and are reported as income or loss from discontinued operations, net of tax, on the Consolidated Statements of Operations.

Other Assets - Other assets include operating lease right of use assets, capitalized software development costs, including cloud computing costs, investments in unconsolidated affiliates accounted for under the equity method, deposits, central parts, and other miscellaneous assets.

•See “Note 7. Leases” for further information on the operating lease right of use assets.

•The Company capitalizes development costs for internal-use software and defers implementation costs for hosting arrangements. Capitalization of software development costs and deferral of implementation costs for hosting arrangements begin in the application development stage and end when the asset is placed into service. The Company amortizes such costs using the straight-line method over estimated useful lives of 2 to 10 years, which is included in Selling, general and administrative expenses or Cost of goods sold within the Consolidated Statements of Operations depending on the nature of the asset and its intended use.

•The Company evaluates its investments in unconsolidated affiliates for impairment whenever events or changes in circumstances indicate that the carrying amount might not be recoverable and recognizes an impairment loss when a decline in value below carrying value is determined to be other-than-temporary. Under these circumstances, the Company would adjust the investment down to its estimated fair value, which then becomes its new carrying value.

•Central parts represent spare production equipment items which are used to replace worn or broken production equipment parts and help reduce the risk of prolonged equipment outages.

Leases -The Company determines whether an arrangement contains an operating or finance lease at inception by determining if the contract conveys the right to control the use of identified plant, property, and equipment for a period of time in exchange for consideration and other facts and circumstances as defined by ASC 842, Leases. For each lease which has an accounting lease term of greater than 12 months, the Company records the right-of-use asset and lease liability on the balance sheet. The accounting lease term includes cancellable and renewal periods which are reasonably assured. The lease liability is measured utilizing the incremental borrowing rate unless the Company can specifically determine the rate implicit in the lease. For leases classified as finance leases at lease inception, the Company records a finance lease asset in Property, plant and equipment, net and lease financing obligation equal to the present value of the minimum lease payments. The finance lease right of use asset is amortized to its expected residual value at the end of the lease term using the straight-line method, and the lease financing obligation is amortized using the effective interest method over the lease term with the rental payments being allocated to principal and interest. For leases classified as operating leases, the Company records the operating lease right of use asset in Other assets and the operating lease obligation in Other accrued liabilities and Other liabilities. Operating lease rent expense is recognized over the useful life using the straight-line method.

Foreign Currency Translation -Assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at the current rate of exchange on the last day of the reporting period. Revenues and expenses are translated at a monthly average exchange rate and equity transactions are translated using either the actual exchange rate on the day of the transaction or a monthly average historical exchange rate. For the fiscal years ended March 31, 2026 and 2025, the Company’s Accumulated other comprehensive loss (“AOCL”) primarily consisted of foreign currency translation gains and losses.

Net Sales -The Company generates revenue by selling pipe and related water management products primarily to distributors, retailers, buying groups and co-operative buying groups. Products are shipped predominately by the Company’s internal fleet, and the Company does not provide any additional revenue generating services after product delivery. Payment terms and conditions vary by contract. Revenue is recognized at the point in-time obligations under the terms of a contract with a customer are satisfied, which generally occurs upon the transfer of control of the promised goods. In substantially all of the Company’s contracts with customers, control is transferred to the customer upon delivery. The Company recognizes revenue in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services.

Shipping Costs -The Company incurs shipping costs to deliver products to customers using an in-house fleet or common carrier. Typically shipping costs are prepaid and included in the product price; however, in some instances, the Company bills shipping costs to customers. Shipping costs are also incurred to physically move raw materials, tooling and products between manufacturing and distribution facilities. Shipping costs to deliver products to customers for the fiscal years ended March 31, 2026, 2025, and 2024 were $369.2 million, $340.8 million, and $284.6 million, respectively, and are included in Cost of goods sold.

Stock-Based Compensation -See “Note 15. Stock-Based Compensation” for information about the stock-based compensation award programs and related accounting policies.

Advertising -The Company expenses advertising costs as incurred. Advertising costs are recorded in Selling, general and administrative expenses in the Consolidated Statements of Operations. The total advertising costs were $14.3 million, $10.6 million, and $10.2 million for the fiscal years ended March 31, 2026, 2025, and 2024, respectively.

Self-Insurance -The Company is self-insured for short-term disability and medical coverage it provides for substantially all eligible employees. The Company is self-insured for medical claims up to the individual and aggregate stop-loss coverage limits. The Company accrues for claims incurred but not reported based on an estimate of future claims related to events that occurred prior to the fiscal year end if it has not met the aggregate stop-loss coverage limit. Amounts expensed totaled $63.3 million, $60.0 million, and $53.3 million for the fiscal years ended March 31, 2026, 2025, and 2024, respectively, of which employees contributed $13.5 million, $13.8 million, and $13.0 million, respectively.

ADS is also self-insured for various other general insurance programs to the extent of the applicable deductible limits on the Company’s insurance coverage. These programs include primarily automobile, general liability, cybersecurity and employment practices coverage with a deductible of $0.5 million per occurrence for general liability and $1 million per occurrence for automobile claim incurred. Amounts expensed during the period, including an estimate for claims incurred but not reported at year end, were $2.9 million, $3.7 million, and $3.1 million, for the years ended March 31, 2026, 2025, and 2024, respectively.

ADS is also self-insured for workers’ compensation insurance with stop-loss coverage for claims that exceed $0.5 million per incident up to the respective state statutory limits. Amounts expensed, including an estimate for claims incurred but not reported, were $5.9 million, $4.7 million, and $4.9 million for the fiscal years ended March 31, 2026, 2025, and 2024, respectively.

Income Taxes -Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized and represent the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. They are measured using the enacted tax rates expected to apply to taxable income in the years in which the related temporary differences are expected to be recovered or settled. Valuation allowances are established against deferred tax assets when it is more likely than not that the realization of those deferred tax assets will not occur. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The deferred income tax provision represents the change during the reporting period in the deferred tax assets and deferred tax liabilities. Penalties and interest recorded on income taxes payable are recorded as part of Income tax expense.

The Company determines whether an uncertain tax position is more likely than not to be sustained upon examination, including resolution of any related appeals or litigation process, based upon the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority.

Fair Values -The fair value framework requires the categorization of assets and liabilities into three levels based upon assumptions (inputs) used to price the assets or liabilities. Level 1 provides the most reliable measure of fair value, whereas Level 3 generally requires significant management judgment. ADS’s policy for determining when transfers between levels have occurred is to use the actual date of the event or change in circumstances that caused the transfer.

Concentrations of Risk -The Company has a large, active customer base of approximately 16,000 customers with two customers, Ferguson and Core & Main, each representing more than 10% of annual net sales. These customers in aggregate accounted for 25.8%,27.0%, and 25.8% of fiscal 2026, 2025 and 2024 net sales, respectively. The Company’s customer base is diversified across the range of end markets that it serves.

Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of Receivables. The Company provides its products to customers based on an evaluation of the customers’ financial condition, generally without requiring collateral. Exposure to losses on Receivables is principally dependent on each customer’s financial condition. The Company performs ongoing credit evaluations of its customers. The Company monitors the exposure for credit losses and maintains allowances for anticipated losses. Concentrations of credit risk with respect to Receivables are limited due to the large number of customers comprising the Company’s customer base and their dispersion across many different geographies. One customer, Ferguson Enterprises, accounted for approximately 10.4% and 19.1% of Receivables at March 31, 2026 and 2025, respectively, and Core & Main accounted for approximately 10.4% of Receivables at March 31, 2025.

Derivatives -The Company recognizes derivative instruments as either assets or liabilities and measures those instruments at fair value. These instruments do not qualify for hedge accounting treatment. ADS uses commodity options in the form of collars and swaps, and foreign currency forward contracts to manage various exposures to commodity price and exchange rate fluctuations. Changes in fair value of the derivative instruments are recognized in Interest income and other, net in the Consolidated Statements of Operations. The Company’s policy is to present all derivative balances on a gross basis.

Interest income and other, net-Included in Interest income and other, net on the Company’s Consolidated Statement of Operations is interest income on invested cash and derivative gains and losses for commodity and foreign currency instruments described below for the fiscal years ended March 31, 2026, 2025, and 2024 were:

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Improvements to Income Tax Disclosures- In December 2023, the FASB issued an accounting Pronouncement (“ASU”) to amend ASC 740, Income Taxes to enhance the transparency and usefulness of income tax disclosures, primarily related to the rate reconciliation and income taxes paid information. The Company adopted this pronouncement retrospectively for the fiscal year ended March 31, 2026 and included the enhanced disclosures. See “Note 16. Income Taxes” for further discussion.

Accounting Pronouncements Not Yet Adopted

Income Statement Expense Disaggregation Disclosures - In November 2024, the FASB issued an ASU requiring disaggregated disclosure of income statement expenses for public business entities. The ASU requires disclosure in tabular format of disaggregation of relevant expense captions presented on the income statement by certain natural expense categories with certain related qualitative disclosures within the notes to the financial statements. The ASU does not change the expense captions an entity presents on the income statement. The ASU is effective for fiscal years beginning after December 15, 2026 and interim reporting periods beginning after December 15, 2027. The Company is currently evaluating the impacts this standard will have on its required disclosures.

Measurement of Credit Losses for Accounts Receivable and Contract Assets- In July 2025, the FASB issued an ASU which amends ASC 326-20 to provide a practical expedient and an accounting policy election related to the estimation of expected credit losses for current accounts receivable and current contract assets that arise from transactions accounted for under ASC 606. An entity is required to disclose whether it has elected to use the practical expedient and, if so, whether it has also applied the accounting policy election. The ASU is effective for fiscal years beginning after December 15, 2025, and interim reporting periods within those annual reporting periods, with early adoption permitted. The new guidance is to be applied prospectively. The Company does not expect the adoption of this standard to have a material impact on the Consolidated Financial Statements.

Accounting for and Disclosure of Software Costs- In September 2025, the FASB issued an ASU which amends certain aspects of ASC 350-40. The amended guidance eliminates project stages and requires capitalizing software costs to begin when (1) management has authorized and committed to funding the software project and (2) it is probable that the project will be completed and the software will be used to perform the function intended. When evaluating if a project is probable to be completed, significant development uncertainty must be assessed. Additionally, disclosures for property, plant and equipment will be required for all capitalized software costs. The ASU is effective for fiscal years beginning after December 15, 2027, and interim reporting periods within those annual reporting periods, with early adoption permitted. The Company is currently evaluating the impact this standard will have on the Consolidated Financial Statements.

2. REVENUE RECOGNITION

Revenue is recognized at the point in-time the obligations under the terms of a contract with a customer are satisfied, which generally occurs upon the transfer of control of the promised goods. In substantially all of the Company’s contracts with customers, control is transferred to the customer upon delivery. The Company recognizes revenue in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. Revenue is presented in the Consolidated Statements of Operations net of allowances for returns, rebates, discounts, and taxes collected concurrently with revenue-producing activities.

The Company disaggregates Stormwater net sales by Domestic and International and further disaggregates Domestic by product type. This disaggregation level best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The following table presents net sales (including intersegment net sales) disaggregated by product type for the Company’s Stormwater and Wastewater segments.

Significant Judgments - The Company’s performance obligation under contracts with customers is to sell and deliver pipe and related water management products. The Company’s contracts with customers may contain multiple performance obligations by promising to deliver multiple products to the customer. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative standalone selling price basis.

The Company’s products are generally sold with a right of return, and the Company may provide credits or incentives, which are accounted for as variable consideration when estimating the amount of revenue to recognize. Variable consideration is estimated at contract inception and updated at the end of each reporting period as additional information becomes available and only to the extent that it is probable that a significant reversal of any incremental revenue will not occur.

Contract Balances - The Company recognizes a contract asset representing the Company’s right to recover products upon the receipt of returned products and a contract liability for the customer refund. The following table presents the balance of the Company’s contract asset and liability as of March 31, 2026 and 2025:

Practical Expedients and Exemptions -The Company applies several practical expedients and exemptions:

•The Company expenses incremental costs to obtain a contract (e.g. sales commissions) when incurred as the amortization period would have been one year or less. These costs are recorded within Selling, general and administrative expenses on the Consolidated Statements of Operations.

•The Company accounts for shipping and handling costs as activities to fulfill the promise to transfer the goods when these activities are performed after a customer obtains control of the goods.

•The Company excludes from the transaction price all sales taxes that are assessed by a governmental authority and that are imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from a customer, for example, sales, use, value added, and some excise taxes.

•Further, the Company does not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

3. RESTRUCTURING AND LOSS (GAIN) ON DISPOSAL OF ASSETS AND COSTS FROM EXIT AND DISPOSAL ACTIVITIES

In fiscal 2026, the Company undertook certain restructuring and realignment activities (the “2026 Restructuring Plan”) to optimize the Company’s production, recycling and distribution network and to plan and implement go-to-market and operating model enhancements to scale for future growth, including the integration of NDS. Under the 2026 Restructuring Plan, for the fiscal year ended March 31, 2026, the Company recorded expense of $48.3 million related to the optimization of the Company’s production, recycling and distribution networks, including the closure of four facilities and changes to the Company’s production footprint. The Company does not currently have an estimate of additional costs or an expected end date for the restructuring actions. The following table summarizes the activities included in Restructuring and realignment expense for the fiscal year ended March 31, 2026:

The costs incurred under the 2026 Restructuring Plan to date are classified as operating expenses and allocated to the Stormwater segment. During the fiscal year ended March 31, 2026, the Company recorded accelerated depreciation, severance costs, impairment of right-of-use lease assets and other exit and disposal costs. Other exit and disposal activities include legal and professional fees, inventory and equipment transfer costs and other costs.

The following table summarizes the restructuring liability for the periods presented:

The restructuring liability is recorded in Other accrued liabilities in the Company’s Consolidated Balance Sheet.

Loss (Gain) on Disposal of Assets - The Company recorded $17.0 million gain on disposal of assets in the fiscal year ended March 31, 2026. The sale of properties previously held-for-sale resulted in the gain of $18.1 million. The remaining balance is due to the sale or disposal of other property, plant and equipment.

For the year ended March 31, 2025, the Company recorded a $3.9 million loss primarily due to the closure of a plant and other asset disposals.

On March 25, 2024, the Company completed its divestiture of substantially all of its Paper Recycling business to a third party purchaser for cash consideration of $7.5 million. The Company recognized a loss on the sale of

$2.0 million in the Consolidated Statements of Operations. Prior to the divestiture, the Company recorded the results of operations in the Stormwater reportable segment.

On April 14, 2023, the Company completed its divestiture of substantially all of the assets of Spartan Concrete, Inc. to a third party purchaser for consideration of $20.0 million. The Company recognized a gain on the sale of $14.9 million in the Consolidated Statements of Operations. Prior to the divestiture, the Company recorded the results of operations in the Stormwater reportable segment.

4. ACQUISITIONS

Acquisition of NDS -On February 2, 2026, the Company completed the acquisition of the water management business of Norma Group SE, known as NDS. NDS expands the Company’s water management offering into complementary products through the addition of NDS’ residential water management, access box and irrigation solutions. The preliminary fair value of consideration transferred was approximately $972.5 million, which represented the purchase price of $984.9 million, net of cash acquired of $3.2 million and cash included in held for sale of $9.2 million. The preliminary purchase price excludes transaction costs. The acquisition was primarily funded from cash on hand. NDS will be included in the Stormwater reportable segment.

Summary of Consideration Transferred - The Company has applied the acquisition method of accounting in accordance with ASC 805, Business Combinations(“ASC 805”) and recognized assets acquired and liabilities assumed at their fair value as of the date of acquisition, with the excess purchase consideration recorded to goodwill. As the Company finalizes the estimation of the fair value of the assets acquired and liabilities assumed, additional adjustments may be recorded during the measurement period (up to one year from the closing date).

The following table summarizes consideration transferred and the preliminary purchase price allocation of identified assets acquired and liabilities assumed:

(a)Upon acquisition, certain NDS entities met the held-for-sale criteria. The Company accordingly classified the associated assets acquired and liabilities assumed as held for sale.

During the period from the Closing Date through March 31, 2026, the Company’s consolidated results of operations included $48.8 million of net sales, $4.7 million of Net loss from continuing operations and $1.1 million of Net loss from discontinued operations associated with the results of operations of NDS. See “Note 5. Discontinued Operations and Assets and Liabilities Held for Sale” for additional information.

The preliminary goodwill of $317.7 million represents the excess of consideration transferred over the preliminary fair value of assets acquired and liabilities assumed and is attributable to expected cross-selling and operating efficiencies. The goodwill is assigned to the Stormwater reportable segment and $271.6 million of the preliminary goodwill is deductible for income tax purposes.

Identifiable Intangible Assets Acquired - The identifiable intangible assets recorded in connection with the acquisition of NDS are based on preliminary valuations including customer relationships, tradename and developed technology totaling $456.9 million. Customer relationships will be amortized using an accelerated method over the useful life. Tradenames and developed technology will be amortized on a straight-line basis over their estimated useful lives. The preliminary fair values and useful lives of acquired intangible assets is presented in the table below.

The preliminary estimate of the fair value of the identifiable intangible assets was determined using the methods described below. The fair value measurements were primarily based on significant inputs that are not observable in the market and thus represent a Level 3 measurement of the fair value hierarchy as defined in ASC 820, Fair Value Measurements (“ASC 820”). Intangible assets consist of acquired customer relationships, patents and developed technology, and tradename and trademarks.

•Customer relationships were valued using the income approach, specifically, the multi-period excess earnings method, which calculates the present value of the estimated revenues and net cash flows derived from the customer relationships.

•Tradename and trademarks were valued using the income approach, specifically, the relief form royalty method, which calculates the present value of hypothetical royalty payments that would be avoided by owning the asset rather than licensing it from a third party.

•Developed technology intangible assets were valued using the income approach, specifically, the relief from royalty method, which calculates the present value of hypothetical royalty payments that would be avoided by owning the technology rather than licensing it from a third party.

Pro Forma Financial Information -The unaudited pro forma information for the fiscal year ended March 31, 2026 presented below includes the effects of the NDS acquisition as if it had been consummated as of April 1, 2024, with adjustments to give effect to pro forma events that are directly attributable to the acquisition of NDS. Adjustments include those related to the depreciation and amortization of acquired fixed and intangible assets, transaction costs, inventory step-up and the estimated tax impacts thereof. The unaudited pro forma information does not reflect any operating efficiency or potential cost savings that could result from the consolidation of NDS. Accordingly, the unaudited pro forma information is presented for informational purposes only and is not necessarily indicative of the actual results of the combined company if the acquisition had occurred at the beginning of the period presented, nor is it indicative of the future results of operations.

During the fiscal year ended March 31, 2026, the Company incurred $40.3 million of transaction costs related to the acquisition such as legal, accounting, valuation and other professional services. These costs are included in selling, general and administrative expenses in the Consolidated Statements of Operations and are reflected in pro forma earnings for the fiscal year ended March 31, 2025 in the table above. These costs are deductible for income tax purposes.

Acquisition of River Valley Pipe - On May 8, 2025, the Company completed its acquisition of the assets of River Valley Pipe LLC (“River Valley Pipe”), a privately-owned pipe manufacturing company located in the Midwest region of the United States. The preliminary fair value of consideration transferred was approximately $18.8 million. The acquisition was funded from cash on hand. River Valley Pipe is included in the Stormwater reportable segment.

The following table summarizes the consideration transferred and the preliminary purchase price allocation of assets acquired and liabilities assumed. The purchase price allocation for assets acquired and liabilities assumed is preliminary and will be finalized when valuations are complete and final assessments of the fair value of acquired assets and assumed liabilities are completed. Such finalization may result in material changes from the preliminary purchase price allocation. The Company's estimates and assumptions are subject to change during the measurement period (up to one year from the closing date), as the Company continues to finalize the valuations of assets acquired and liabilities assumed.

The preliminary goodwill of $3.9 million represents the excess of consideration transferred over the preliminary fair value of assets acquired and liabilities assumed and is attributable to expected operating efficiencies. The goodwill is deductible for income tax purposes and is assigned to Stormwater.

The preliminary purchase price excludes transaction costs. During the fiscal year ended March 31, 2026, the Company incurred $0.5 million of transaction costs related to the acquisition such as legal, accounting, valuation and other professional services. These costs are included in selling, general and administrative expenses in the Consolidated Statements of Operations.

The identifiable intangible assets recorded in connection with the acquisition of River Valley Pipe are based on preliminary valuations including customer relationships and tradename totaling $3.0 million. The intangible assets will be amortized on a straight-line basis over their estimated useful lives.

The Company has excluded certain disclosures required under ASC 805, Business Combinations as they are not material to the financial statements.

Acquisition of Orenco -On October 1, 2024, the Company’s wholly-owned subsidiary, Infiltrator, completed the acquisition of Orenco Systems, Inc. (“Orenco”), a leading manufacturer of decentralized wastewater management products serving residential and non-residential end markets. The fair value of consideration transferred was approximately $236.3 million, which represented the purchase price of $255.0 million, net of cash acquired of $18.7 million. The acquisition was funded from cash on hand. Orenco is included in the Wastewater reportable segment.

The following table summarizes the consideration transferred and the purchase price allocation of assets acquired and liabilities assumed:

The goodwill of $104.2 million represents the excess of consideration transferred over the fair value of assets acquired and liabilities assumed and is attributable to expected operating efficiencies. The goodwill is not deductible for income tax purposes and is assigned to Wastewater.

The purchase price excludes transaction costs. During the fiscal year ended March 31, 2025, the Company incurred $7.5 million of transaction costs related to the acquisition such as legal, accounting, valuation and other professional services. These costs are included in selling, general and administrative expenses in the Consolidated Statements of Operations.

The identifiable intangible assets recorded in connection with the acquisition of Orenco include customer relationships, developed technology and tradename totaling $148.0 million. The intangible assets will be amortized on a straight-line basis over their estimated useful lives.

The Company has excluded certain disclosures required under ASC 805, Business Combinations as they are not material to the financial statements.

5. DISCONTINUED OPERATIONS AND ASSETS AND LIABILITIES HELD FOR SALE

As discussed in “Note 1. Background and Summary of Significant Accounting Policies,” the NDS International Entities met the held for sale criteria upon acquisition. As a result, the assets and liabilities of the NDS International Entities have been classified held for sale and are reported as assets held for sale and liabilities held for sale on the Consolidated Balance Sheet. The results of the NDS International Entities have been accounted for as discontinued operations and are reported as income or loss from discontinued operations, net of tax, for the period from the date of acquisition to March 31, 2026 on the Consolidated Statements of Operations.

The Company measured the net assets of the disposal group at fair value less costs to sell. Costs to sell represent incremental direct costs expected to be incurred in connection with the disposal. Fair value was determined based on the valuation techniques noted in “Note 4. Acquisitions.”The assets and liabilities classified as held for sale on the Company’s Consolidated Balance Sheet as of March 31, 2026, include the following:

The following table summarizes the major classes of items constituting the results from discontinued operations for presented in the Consolidated Statement of Operations for fiscal year 2026:

6. PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment, net as of the fiscal years ended March 31 consisted of the following:

Depreciation expense related to Property, plant and equipment in each of the fiscal years ended March 31 was:

7. LEASES

Nature of the Company’s Leases - The Company has operating and finance leases for plants, yards, corporate offices, tractors, trailers and other equipment. The Company’s leases have remaining terms of less thanone year to 12 years. A portion of the Company’s real estate leases include an option to extend the leases for up to 5 years. The

Company has included renewal options which are reasonably certain to be exercised in its right-of-use assets and lease liabilities. The Company’s lease payments are generally fixed.

Supplemental balance sheet information related to leases as of the periods presented was as follows:

Lease Cost - The components of lease cost for the years ended March 31, 2026, 2025, and 2024 were:

Supplemental cash flow information related to leases for the periods presented were as follows:

The following is a schedule by year of future minimum lease payments on a rolling twelve-month basis under operating and finance leases and the present value of the net minimum lease payments as of March 31, 2026:

8. INVENTORIES

Inventories as of the fiscal years ended March 31 consisted of the following:

During fiscal years ended March 31, 2026 and 2025, the Company incurred production-related general and administrative costs included in the cost of finished goods inventory of $65.8 million and $62.6 million, respectively, of which $18.5 million and $18.1 million remained in inventory at March 31, 2026 and 2025, respectively.

9. GOODWILL AND INTANGIBLE ASSETS

Goodwill -The carrying amount of goodwill by reportable segment is as follows:

Intangible Assets- Intangible assets as of March 31, 2026 and 2025 consisted of the following:

(a)Indefinite-lived intangible assets may fluctuate as a result of foreign currency translation.

The following table presents the amortization expense and weighted average amortization period for definite-lived intangible assets at March 31, 2026:

Future intangible asset amortization expense based on existing intangible assets at March 31, 2026 is:

10. FAIR VALUE MEASUREMENT AND DERIVATIVE TRANSACTIONS

When applying fair value principles in the valuation of assets and liabilities, the Company is required to maximize the use of quoted market prices and minimize the use of unobservable inputs. The Company has not changed its valuation techniques used in measuring the fair value of any financial assets or liabilities during the fiscal periods presented. The fair value estimates take into consideration the credit risk of both the Company and its counterparties.

When active market quotes are not available for financial assets and liabilities, the Company uses industry standard valuation models. Where applicable, these models project future cash flows and discount the future amounts to present value using market-based observable inputs including credit risk, interest rate curves, foreign currency rates and forward and spot prices for currencies. In circumstances where market-based observable inputs are not available, management judgment is used to develop assumptions to estimate fair value.

Derivatives -A summary of the fair values for the various derivatives, which are all measured using Level 2 inputs, at March 31, 2026 and 2025 is presented below:

There were no transfers in or out of Level 3 for the fiscal years ended March 31, 2026 and 2025.

Valuation of Debt -The carrying amounts of current financial assets and liabilities approximate fair value because of the immediate or short-term maturity of these items, or in the case of derivative instruments, because they are recorded at fair value. The following table presents the carrying and fair value of the Company’s 2027 Notes, 2030 Notes, 2034 Notes and Equipment Financing (as further discussed in “Note 13. Debt”) for the periods presented:

The fair values of the 2027 Notes, 2030 Notes and 2034 Notes were determined based on quoted market data for the Company’s 2027 Notes, 2030 Notes and 2034 Notes, respectively. The fair value of the Equipment Financing was determined based on a comparison of the interest rate and terms of such borrowings to the rates and terms of similar debt available for the period. The categorization of the framework used to evaluate the 2027 Notes, 2030 Notes, 2034 Notes and Equipment Financing are considered Level 2. The Company believes the carrying amount on the remaining long-term debt, including the Term Loan Facility, Revolving Credit Facility and Commercial loan agreement, is not materially different from its fair value as the interest rates and terms of the borrowings are similar to currently available borrowings.

11. INVESTMENT IN AFFILIATES

ADS Mexicana -ADS hasone consolidated joint venture, ADS Mexicana, which is 51% owned by the Company’s wholly-owned subsidiary ADS Worldwide, Inc. The equity owned by the Company’s joint venture partner is shown as Noncontrolling interest in subsidiaries in the Consolidated Balance Sheets and the joint venture partner’s portion of net income is shown as Net income attributable to noncontrolling interest in the Consolidated Statements of Operations.

ADS participates in joint ventures for the purpose of expanding upon the growth of manufacturing and selling HDPE corrugated pipe in emerging markets. ADS invested in ADS Mexicana for the purpose of expanding upon growth of manufacturing and selling ADS licensed HDPE corrugated pipe and related products in the Mexican and Central American markets via the joint venture partner’s local presence and expertise throughout the region. The Company executed a Technology, Patents and Trademarks Sub-License Agreement and a Distribution Agreement with ADS Mexicana that provides ADS Mexicana with the rights to manufacture and sell ADS licensed products in Mexico and Central America. The Company has concluded that it holds a variable interest in and is the primary beneficiary of ADS Mexicana based on the power to direct the most significant activities of ADS Mexicana and the obligation to absorb losses and the right to receive benefits that could be significant to ADS Mexicana. As the primary beneficiary, the Company is required to consolidate the assets and liabilities of ADS Mexicana.

The table below includes the assets and liabilities of ADS Mexicana that are consolidated as of March 31, 2026 and 2025. The balances exclude intercompany transactions that are eliminated upon consolidation.

EQ TruePointe One - The Company has 63% ownership of a consolidated joint venture, which owns and operates the Company’s corporate headquarters building. The equity owned by the Company’s joint venture partners is shown as Noncontrolling interest in subsidiaries in the Consolidated Balance Sheets and the joint venture partners’ portion of net income is shown as Net income attributable to noncontrolling interest in the Consolidated Statements of Operations. The Company has concluded that it holds a variable interest in and is the primary beneficiary of EQ TruePointe One based on the power to direct the most significant activities of the entity and the obligation to absorb losses and the right to receive benefits that could be significant. As the primary beneficiary, the Company is required to consolidate the assets and liabilities of EQ TruePointe One.

The table below includes the assets and liabilities of EQ TruePointe One that are consolidated as of March 31, 2026. The balances exclude intercompany transactions that are eliminated upon consolidation.

South American Joint Venture -The Company participates in an unconsolidated joint venture, the South American Joint Venture, which is 50% owned by the Company’s wholly-owned subsidiary ADS Chile. The Company’s investment in this unconsolidated joint venture was formed for the purpose of expanding upon the growth of manufacturing and selling HDPE corrugated pipe in the South American market via the joint venture partner’s local presence and expertise throughout the region. The Company has concluded that it is appropriate to account for this investment using the equity method, whereby the Company’s share of the income or loss of the joint venture is reported in the Consolidated Statements of Operations under Equity in net income of unconsolidated affiliates and the Company’s investment in the joint venture is included in Other assets in the Consolidated Balance Sheets. The Company is not required to consolidate the South American Joint Venture as it is not the primary beneficiary, although the Company does hold significant variable interests in the South American Joint Venture through the equity investment and debt guarantee.

12. RELATED PARTY TRANSACTIONS

ADS Mexicana - On June 6, 2022, the Company and ADS Mexicana amended the Intercompany Revolving Credit Promissory Note (the “Intercompany Note”) with a borrowing capacity of $9.5 million. The Intercompany Note matures on June 8, 2027. The Intercompany Note indemnifies the ADS Mexicana joint venture partner for 49% of any unpaid borrowing. The interest rates under the Intercompany Note are determined by certain base rates or Secured Overnight Financing Rate (“SOFR”) plus an applicable margin based on the Leverage Ratio. As of March 31, 2026 and 2025, there wereno borrowings under the Intercompany Note.

South American Joint Venture -ADS is the guarantor for 50% of the South American Joint Venture’s credit facility, and the debt guarantee is shared equally with the joint venture partner. The maximum potential obligation under this guarantee totals $5.5 million as of March 31, 2026. The maximum borrowing permitted under the South American Joint Venture’s credit facility is $11.0 million. This credit facility allows borrowings in either Chilean pesos or U.S. dollars at a fixed interest rate determined at inception of each draw on the facility. The guarantee of the South American Joint Venture’s debt expires on December 31, 2026. ADS does not anticipate any required contributions related to the balance of this credit facility. As of March 31, 2026 and 2025, there wasno outstanding principal balance or U.S. dollar denominated loans.

13. DEBT

Long-term debt as of the fiscal years ended March 31 consisted of the following:

Senior Secured Credit Facility -On July 31, 2019, the Company entered into a credit agreement (the “Base Credit Agreement”) by and among, the Company, as borrower, Barclays Bank PLC, as administrative agent, and the several lenders from time to time party thereto. Among other things, the Base Credit Agreement provided for a term loan facility in the initial aggregate principal amount of $1.3 billion (the “Initial Term Loan Facility”) and a revolving credit facility in an initial aggregate amount of up to $350 million (the “Initial Revolving Credit Facility”), which included a sub-limit for a letter of credit sub-facility in the initial aggregate amount of up to $50 million. On September 24, 2019, the Company entered into a First Amendment (the “First Amendment”) to the Company’s Base Credit Agreement subsequent to the common stock offering and Senior Notes due in 2027.

On May 26, 2022, the Company entered into a Second Amendment (the “Second Amendment”) to the Company's Base Credit Agreement with, among others, Barclays Bank PLC, as administrative agent under the Initial Term Loan Facility, and PNC Bank, National Association, as new administrative agent under the Initial Revolving Credit Facility. Among other things, the Second Amendment (i) amended the Base Credit Agreement by increasing the Initial Revolving Credit Facility (the “Second Amended Revolving Credit Facility”) from $350 million to $600 million (including an increase of the sub-limit for the swing-line sub-facility (“the L/C facility”) from$50 million to $60 million) and extended the maturity date of the Revolving Credit Facility to the earlier of May 26, 2027 or the date that is six months prior to the earliest maturity date of the outstanding loans under the Initial Term Loan Facility.

On February 27, 2026, the Company entered into a Fourth Amendment (the “Fourth Amendment”) to the Company’s Base Credit Agreement (the Base Credit Agreement as amended by the First Amendment, the Second Amendment, the Third Amendment and the Fourth Amendment, the “Credit Agreement”) with, among others, certain subsidiaries of the Company, as guarantors, Bank of America, N.A., as administrative agent under the Term Loan Facility (as defined below) and PNC Bank, National Association, as administrative agent under the Revolving Credit Facility (as defined below) and as successor administrative agent, Barclays Bank PLC, as predecessor administrative agent, and the several financial institutions from time to time party thereto as lenders. Among other things, the Fourth Amendment (i) increased the Amended Revolving Credit Facility from$600 million to $750 million (the “Revolving Credit Facility”), including an increase of the sub-limit for the letter of credit sub-facility from$60 million to $75 million, (ii) refinanced the outstanding amounts owing under the Initial Term Loan Facility by providing for a new term loan facility in the initial aggregate principal amount of $600 million (the “Term Loan Facility”), (iii) extended the maturity date of the Revolving Credit Facility to February 27, 2031, (iv) extended the maturity date of the Term Credit Facility to February 28, 2033, (v) revised the “applicable margin” to provide for a range of 125 basis points to 225 basis points (for Term Benchmark based loans) and 25 basis points to 125 basis points (for base rate loans), as determined based on the consolidated senior secured net leverage ratio ranging from less than 1.50 to 1.00 to greater than or equal to 3.50 to 1.00, (vi) provides for incremental facilities in the aggregate maximum amount of the greater of $350 million or 100% of consolidated EBITDA for the most recently ended four consecutive fiscal quarters, and (vii) amended certain covenant baskets under the Credit Agreement to align with the growth of the Company.

Letters of credit outstanding at March 31, 2026 and 2025 amounted to $10.1 million and $9.5 million, respectively, and reduced the availability of the Revolving Credit Facility.

At the option of the Company, borrowings under the Term Loan Facility and under the Revolving Credit Facility (subject to certain limitations) bear interest at either a base rate (as determined pursuant to the Fourth Amendment) or at a Term Benchmark rate (as defined in the Fourth Amendment), plus the applicable margin as set forth therein from time to time. In the case of the Revolving Credit Facility, the applicable margin is based on the Company's consolidated senior secured net leverage ratio (as defined in the Fourth Amendment). All borrowings under the Term Loan Facility as described above initially bear interest at the Term Benchmark rate (as defined in the Fourth Amendment). In the case of the Term Loan Facility, the applicable margin shall be, for loans bearing interest at the Term Benchmark rate,1.625%, and for loans bearing interest at the base rate,0.625%. The deferred financing costs associated with the amendment to the Revolving Credit Facility totaled $3.6 million and are recorded as Other assets on the Company’s Consolidated Balance Sheet.

The Company is also required to pay a commitment fee that is based upon the undrawn amounts of the Revolving Credit Facility at a rate per annum based upon a calculated ratio as prescribed within the Credit Agreement. As of March 31, 2026, the rate the Company was committed to paying on the undrawn portion was equal to 0.15%.

The Company’s obligations under the Credit Agreement have been secured by granting a first priority lien on substantially all of the Company’s assets (subject to certain exceptions and limitations), and each of StormTech, LLC, Infiltrator Water Technologies, LLC, and Orenco Systems, Inc. (collectively the “Guarantors”) has agreed to guarantee the obligations of the Company under the Credit Agreement and to secure the obligations thereunder by granting a first priority lien in substantially all of such Guarantor's assets (subject to certain exceptions and limitations).

Senior Notes due 2027 -On September 23, 2019, the Company issued $350.0 million aggregate principal amount of 5.0% 2027 Notes pursuant to the 2027 Indenture among the Company, the Guarantors and the Trustee. The 2027 Indenture contained customary events of default, including, among other things, payment default, failure to comply with covenants or agreements contained in the 2027 Indenture or the 2027 Notes and certain provisions related to bankruptcy events. The 2027 Indenture also contained customary negative covenants. The 2027 Notes were guaranteed by each of the Company’s present and future direct and indirect wholly-owned domestic subsidiaries that was a guarantor under the Company’s Senior Secured Credit Agreement. Interest on the 2027 Notes was payable semi-annually in cash in arrears on March 31 and September 30 of each year, commencing on March 31, 2020, at a rate of 5.0% per annum. The 2027 Notes were scheduled to mature on September 30, 2027. The Company used the majority of the net proceeds from the offering of the 2027 Notes for the repayment of $300.0 million of its outstanding borrowings. The deferred financing costs associated with the 2027 Notes totaled $2.1 million and were recorded as a direct reduction from the carrying amount of the related debt. The Company was able to redeem the 2027 Notes, in whole or in part, at any time on or after September 30, 2022 at established redemption prices. On February 27, 2026, the Company redeemed all of its outstanding 2027 Notes in the original aggregate principal amount of $350.0 million at a redemption price equal to 100% of the principal amount plus accrued and unpaid interest, to, but excluding, the redemption date in connection with its issuance of $500.0 million aggregate principal amount of the 2034 Notes.

Senior Notes due 2030- On June 9, 2022, the Company issued $500.0 million aggregate principal amount of 6.375% 2030 Notes pursuant to the 2030 Indenture, among the Company, the Guarantors and the Trustee. The 2030 Indenture contains customary events of default, including, among other things, payment default, failure to comply with covenants or agreements contained in the 2030 Indenture or the 2030 Notes and certain provisions related to bankruptcy events. The 2030 Indenture also contains customary negative covenants. Interest on the 2030 Notes will be payable semi-annually in cash in arrears on January 15 and July 15 of each year, commencing on January 15, 2023, at a rate of 6.375% per annum. The 2030 Notes will mature on July 15, 2030. The Company used a portion of the net proceeds from the offering of the 2030 Notes to repay in full the outstanding borrowings under its Revolving Credit Facility and will use the remainder for general corporate purposes. The deferred financing costs associated with the 2030 Notes totaled $9.0 million and are recorded as a direct reduction from the carrying amount of the related debt.

The Company may redeem the 2030 Notes, in whole or in part, at any time on or after July 15, 2025 at certain specified redemption prices set forth in the 2030 Indenture. In addition, at any time prior to July 15, 2025, the Company may redeem the 2030 Notes, in whole or in part, at a redemption price equal to 100% of the principal amount of the 2030 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date plus an applicable “make-whole” premium. At any time prior to July 15, 2025, the Company may also redeem up to 40% of the aggregate principal amount of 2030 Notes issued under the Indenture with net cash proceeds of certain equity offerings at a redemption price equal to 106.375% of the principal amount of the 2030 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date.

Senior Notes due 2034- On February 27, 2026, the Company issued $500.0 million aggregate principal amount of 5.375% 2034 Notes pursuant to the 2034 Indenture, among the Company, the Guarantors and the Trustee. The 2034 Indenture contains customary events of default, including, among other things, payment default, failure to comply with covenants or agreements contained in the 2034 Indenture or the 2034 Notes and certain provisions related to bankruptcy events. The 2034 Indenture also contains customary negative covenants. Interest on the 2034 Notes will be payable semi-annually in cash in arrears on March 1 and September 1 of each year, commencing on September 1, 2026, at a rate of 5.375% per annum. The 2034 Notes will mature on March 1, 2034. The Company used the net proceeds from the offering of the 2034 Notes, together with the proceeds of the term loan “B” portion of its existing senior secured credit facility, to refinance the outstanding balance of the Company’s senior secured credit facility and redeem the 2027 Notes in full, with the remainder for general corporate purposes. The deferred financing costs associated with the 2034 Notes totaled $7.5 million and are recorded as a direct reduction from the carrying amount of the related debt.

The Company may redeem the 2034 Notes, in whole or in part, at any time on or after March 1, 2029 at certain specified redemption prices set forth in the 2034 Indenture. In addition, at any time prior to March 1, 2029, the Company may redeem the 2034 Notes, in whole or in part, at a redemption price equal to 100% of the principal amount of the 2034 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date plus an applicable “make-whole” premium. At any time prior to March 1, 2029, the Company may also redeem up to 40% of the aggregate principal amount of 2034 Notes issued under the 2034 Indenture with net cash proceeds of certain equity offerings at a redemption price equal to 105.375% of the principal amount of the 2034 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date

Other debt -Other debt includes equipment financing and the commercial loan related to the Company’s headquarters. In November 2021, the Company purchased material handling equipment, trucks and trailers previously leased under a master lease agreement and classified as finance leases. The purchase was funded with debt through the Master Lease Agreement and Interim Funding Schedule with Fifth Third. The assets acquired are titled to the Company and included in Property, plant and equipment, net on the Company's Consolidated Balance Sheet. The equipment financings have a term of between 12 and 84 months, based on the life of the equipment, and bear a weighted average interest of 1.8%. The current portion of the equipment financing is $1.1 million, and the long-term portion is $1.9 million at March 31, 2026.

The Company entered into a commercial loan agreement of $27.2 million which matures on December 5, 2028. The agreement bears interest based on SOFR plus a margin of 285 basis points, requires interest only payments through December 5, 2026, and beginning January 5, 2027 through maturity, includes principal and interest payments.

Principal Maturities -Maturities of long-term debt (excluding interest and deferred financing costs) as of March 31, 2026 are summarized below:

14. EMPLOYEE BENEFIT PLANS

KSOP Retirement Plan (“KSOP”) -The Company’s KSOP holds shares of redeemable common stock. The common stock held by the KSOP is classified as mezzanine equity as the shares are subject to theput option requirements of the Internal Revenue Code. When participants sell or forfeit these shares, the shares would no longer be subject to the put option of the Internal Revenue Code and would no longer required to be classified in mezzanine equity.

Profit-Sharing Retirement Plan -On April 11, 2022, the ESOP was merged into the existing 401(k) retirement plan effective April 1, 2022 creating the KSOP. The tax-qualified profit-sharing retirement plan has a 401(k) feature covering substantially all U.S. eligible employees. Except for employer matching contributions made on behalf of Infiltrator employee-participants, the Company made employer contributions of $15.1 million, $14.2 million and $9.2 million in the fiscal years ended March 31, 2026, 2025, and 2024 respectively.

Redeemable Common Stock -The put option requirements of the Internal Revenue Code apply in the event that the Company’s common stock is not a registration type class of security, or its trading has been restricted. Therefore, the holders of common stock within the KSOP have a put right to require the Company to repurchase such shares in the event that the common stock is not listed for trading or otherwise quoted on the NYSE, AMEX, NASDAQ, or any other market more senior than the OTC Bulletin Board.

Defined Contribution Postretirement Plan -The Company has defined contribution postretirement benefit plans covering Canadian employees. The Company recognized costs of $2.1 million, $2.2 million and $2.0 million in the fiscal years ended March 31, 2026, 2025, and 2024, respectively.

15. STOCK-BASED COMPENSATION

The Company has several programs for stock-based payments to employees and directors, including stock options, performance-based restricted units and restricted stock. Compensation expense is recognized on a straight-line basis over the employee’s requisite service period, which is generally the vesting period of the grant. The Company recognized stock-based compensation expense in the following line items on the Consolidated Statements of Operations for the fiscal years ended March 31, 2026, 2025, and 2024:

The following table summarizes stock-based compensation expense by award type for the fiscal years ended March 31, 2026, 2025, and 2024:

2017 Omnibus Plan

The 2017 Omnibus Plan Incentive Plan, as amended in July 2021, (the “2017 Omnibus Plan”) provides for the issuance of a maximum of 5.0 million shares of the Company’s common stock for awards made thereunder, which awards may consist of stock options, restricted stock, restricted stock units, stock appreciation rights, phantom stock, cash-based awards, performance awards (which may take the form of performance cash, performance units or performance shares) or other stock-based awards. The Company had approximately 1.5 million shares available for awards as of March 31, 2026.

Stock Options -Stock option awards are measured based on the grant date estimated fair value of each award. The Company estimates the fair value of stock options using a Black-Scholes option-pricing model. The following table summarizes the assumptions used in estimating the fair value of stock options:

The stock option activity for the fiscal year ended March 31, 2026 is summarized as follows:

As of March 31, 2026, there was a total of $8.2 million of unrecognized compensation expense related to unvested stock option awards under the 2017 Omnibus Plan, as amended, that will be recognized as an expense as the awards vest over the remaining weighted average service period of 1.7 years. All outstanding options are expected to vest. The aggregate intrinsic value for options outstanding and exercisable as of March 31, 2026 was $53.4 million and $49.2 million, respectively. The total intrinsic value of options exercised during the fiscal years ended March 31, 2026, 2025, and 2024 were $14.0 million, $20.0 million and $12.1 million, respectively.

Restricted Stock -The information about the unvested restricted stock grants as of March 31, 2026 is as follows:

At March 31, 2026, there was approximately $17.5 million of unrecognized compensation expense related to the restricted stock that will be recognized over the weighted average remaining service period of 1.8 years. The total fair value of restricted stock that vested during fiscal year ended March 31, 2026, 2025 and 2024 was $12.5 million, $15.0 million and $8.4 million, respectively. The fair value of restricted stock is based on the fair value of the Company’s common stock at the date of grant.

Performance-based Restricted Units (“Performance units”) -The information about the performance units granted under the 2017 Omnibus Plan is as follows:

At March 31, 2026, there was approximately $13.7 million of unrecognized compensation expense related to the performance units that will be recognized over the weighted average remaining service period of 1.9 years. Forthe performance units granted in fiscal 2026, 2025 and 2024,50% of the award is based upon the achievement of certain levels of Return on Invested Capital for the performance period and 50% is based upon the achievement of certain levels of cash flows from operations for the performance period or other specific project targets. The performance units each have a 3-year performance period. The performance units, and any accrued dividend equivalents, will be settled in shares of the Company’s common stock, if the applicable performance and service conditions are satisfied. The fair value of performance-based restricted stock units is based on the fair value of the Company’s common stock at the date of grant.

2013 Stock Option Plan

The Company’s 2013 stock option plan (“2013 Plan”) generally provided for grants of stock options with the exercise price equal to fair value on the date of grant. The grants generally vest inthree tofive equal annual amounts beginning in year one and expire after approximately 10 years from issuance. The Company hadno shares available for grant under the 2013 Plan as of March 31, 2026. The stock option activity for the fiscal year ended March 31, 2026 is summarized as follows:

The total intrinsic value of options exercised during the fiscal year ended March 31, 2026, 2025, and 2024 were $1.7 million, $10.9 million and $1.8 million, respectively.

Employee Stock Purchase Plan (“ESPP”) -The Advanced Drainage Systems, Inc. Employee Stock Purchase Plan, which provides for a maximum of 0.4 million shares of the Company’s common stock. Eligible employees may purchase the Company's common stock at 85% of the lower of the fair market value of the Company's common stock on the first day or the last day of the offering period.

16. INCOME TAXES

Provision for Taxes -The components of Income before income taxes for the fiscal years ended March 31 are as follows:

The components of Income tax expense for the fiscal years ended March 31 consisted of the following:

For the fiscal years ended March 31, the effective tax rate varied from the statutory Federal income tax rate as a result of the following factors:

(a) In 2026, state and local taxes in Florida, California, Georgia, North Carolina, Pennsylvania, and Alabama comprised the majority (greater than 50%) of the tax effect in this category. In 2025, state and local taxes in Florida, California, Georgia, North Carolina, Massachusetts, Oregon, and Pennsylvania comprised the majority (greater than 50%) of the tax effect in this category. In 2024, state and local taxes in Florida, California, Georgia, Pennsylvania, New Jersey, North Carolina, and Alabama comprised the majority (greater than 50%) of the tax effect in this category.

Cash Taxes Paid -The income taxes paid (net of refunds received) for the fiscal years ended March 31 are as follows:

Deferred Income Taxes -Net deferred tax assets and liabilities are included in Other assets and Deferred tax liabilities, respectively, on the Consolidated Balance Sheets. The related balances at March 31 were as follows:

The tax effect of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at March 31 were comprised of:

As a result of the NDS International Entities being classified as held for sale, the Company has recorded deferred tax assets of $12.7 million as of March 31, 2026 related to net losses on outside basis differences. A valuation allowance has been recorded against $7.3 million of these deferred tax assets as of March 31, 2026. See “Note 5. Discontinued Operations and Held for Sale” for additional information.

The Company intends to repatriate earnings from Canada and believes that there will be no additional tax costs associated with the repatriation of such earnings other than any potential non-U.S. withholding taxes, for which no deferred tax liability has been recognized. All other undistributed earnings from other foreign entities are intended to be reinvested indefinitely with the exception of cash dividends paid by the Company’s ADS Mexicana joint venture. It is not practicable to estimate the amount of deferred tax liability, which would primarily relate to withholding tax, that might be payable on the eventual remittance of such undistributed earnings.

Uncertain Tax Positions -A reconciliation of the balance of unrecognized tax benefits for the years ended March 31 is as follows:

Included in the balance of unrecognized tax benefits at March 31, 2026, 2025, and 2024 were $12.2 million, $7.5 million and $3.6 million, respectively, of tax benefits that if recognized would favorably affect the Company’s effective tax rate.

The unrecognized tax benefit is recorded in Other accrued liabilities, Liabilities held for sale, and Other liabilities in the Company’s Consolidated Balance Sheet. These amounts include potential accrued interest and penalties of $0.7 million and $0.4 million at March 31, 2026 and 2025, respectively.

The Company is currently open to audit under the statute of limitations by the IRS for the fiscal years ended March 31, 2023 through March 31, 2026. The majority of the Company’s state income tax returns are open to audit under the statute of limitations for the years ended March 31, 2022 through March 31, 2026. The foreign income tax returns are open to audit under the statute of limitations for the years ended March 31, 2022 through March 31, 2026.

17. NET INCOME PER SHARE AND STOCKHOLDERS’ EQUITY

Basic net income per share is calculated by dividing the Net income available to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net income per share is computed by dividing the Net income available to common stockholders by the weighted-average number of common stock equivalents outstanding for the period.

The following table presents information necessary to calculate net income per share for the fiscal years ended March 31, 2026, 2025, and 2024, as well as potentially dilutive securities excluded from the weighted average number of diluted common shares outstanding because their inclusion would have been anti-dilutive:

Stockholders’ Equity - In February 2026, the Board of Directors approved a new $1.0 billion stock repurchase authorization (the “Repurchase Program”) of ADS common stock in accordance with applicable securities laws. The repurchase program does not obligate the Company to acquire any particular amount of common stock and may be suspended or terminated at any time at the Company’s discretion. The Company repurchased 0.7 million and 0.4 million shares of common stock at a cost of $99.2 million and $68.2 million during the fiscal year March 31, 2026 and 2025, respectively.

18. COMMITMENTS AND CONTINGENCIES

Purchase Commitments -The Company has historically secured supplies of resin raw material by agreeing to purchase quantities during a future given period at a fixed price. These purchase contracts typically range from 1 to 12 months and occur in the ordinary course of business. The Company doesnot have any outstanding purchase commitments with fixed price and quantity as of March 31, 2026. The Company also enters into equipment purchase contracts with manufacturers.

Litigation and Other Proceedings -The Company is involved from time to time in various legal proceedings that arise in the ordinary course of business, including but not limited to commercial disputes, environmental matters, employee related claims, intellectual property disputes and litigation in connection with transactions including acquisitions and divestitures. The Company does not believe that such litigation, claims, and administrative proceedings will have a material adverse impact on the Company’s financial position or results of operations. The Company records a liability when a loss is considered probable, and the amount can be reasonably estimated.

19. OTHER ACCRUED LIABILITIES

Other accrued liabilities as of fiscal years ended March 31 consisted of the following:

20. BUSINESS SEGMENT INFORMATION

Following the acquisition of NDS the Company realigned its reportable segments to align with the manner in which the CODM assesses performance and makes resource allocation decisions. ADS operates its business intwo distinct reportable segments: “Stormwater” and “Wastewater”, which are primarily organized based on products. The CODM for ADS is the Chief Executive Officer (“CEO”). The CEO reviews financial information and makes operational decisions based on Net sales and a measure of operating profit, Segment Adjusted EBITDA, a non-GAAP financial measure.

Certain selling and general and administrative expenses are not allocated to the segments, including non-operating functions such as legal, facilities management, and investor relations. A measure of assets is not applicable, as segment assets are not regularly reviewed by the CODM for evaluating performance or allocating resources. The Company does not aggregate operating segments to form reportable segments.

Stormwater - The Stormwater segment manufactures and markets high performance thermoplastic corrugated pipe and complementary products, including single wall pipe, N-12 HDPE pipe, high performance polypropylene pipe, StormTech, Nyloplast, Inserta Tee, Cultec, water quality filters and structures, Fittings, FlexStorm and NDS channel drains, catch basins and access boxes. Stormwater products are sold throughout the United States and certain international regions, including Company owned facilities in Canada, subsidiaries that distribute to Europe and the Middle East, and exports through the Company’s joint ventures with local partners in Mexico and South America. The Company maintains and serves these markets through product distribution relationships with many of the largest waterworks distributors, buying groups and co-ops, major retailers as well as an extensive network of hundreds of small to medium-sized distributors. Products are designed primarily for stormwater management in the construction and infrastructure marketplace across a broad range of end markets and applications, including non-residential, residential, agriculture and infrastructure.

Wastewater - Wastewater (formerly Infiltrator) is a leading national provider of plastic leachfield chambers and systems, onsite wastewater tanks and accessories, primarily for use in residential applications. Infiltrator products are used in onsite wastewater treatment systems in the United States and Canada.

The following tables set forth Net sales, significant segment expenses, and Adjusted EBITDA for each of the Company’s reportable segments for the fiscal years ended March 31:

(a)Other segment items include depreciation, amortization recorded within cost of goods sold, stock-based compensation expense, inventory step-up costs, restructuring and realignment expense, and transaction costs.

(b)The Company calculates Segment Adjusted EBITDA as net income from continuing operations before interest, income taxes, depreciation and amortization, stock-based compensation expense, non-cash charges and certain other gains and expenses.

(e)Includes derivative fair value adjustments, foreign currency transaction (gains) losses, legal settlements, inventory step-up costs, restructuring and realignment expense, and executive retirement expense (benefit).

(a)Other segment items include depreciation, amortization recorded within cost of goods sold, stock-based compensation expense, inventory step-up cost, restructuring and realignment expense, and transaction costs.

(b)The Company calculates Segment Adjusted EBITDA as net income from continuing operations before interest, income taxes, depreciation and amortization, stock-based compensation expense, non-cash charges and certain other gains and expenses.

(e)Includes derivative fair value adjustments, foreign currency transaction (gains) losses, legal settlements, inventory step-up costs, restructuring and realignment expense, and executive retirement expense (benefit).

(a)Other segment items include depreciation, amortization recorded within cost of goods sold, stock-based compensation expense, inventory step-up costs, restructuring and realignment expense, and transaction costs.

(b)The Company calculates Segment Adjusted EBITDA as net income from continuing operations before interest, income taxes, depreciation and amortization, stock-based compensation expense, non-cash charges and certain other gains and expenses.

(e)Includes derivative fair value adjustments, foreign currency transaction (gains) losses, legal settlements, inventory step-up costs, restructuring and realignment expense, and executive retirement expense (benefit).

Other Segment Information-The following sets forth certain financial information for the fiscal years ended March 31:

Geographic Sales and Assets Information -Net sales are attributed to the geographic location based on the location of the customer. The table below represents the Net sales and long-lived asset information by geographic location for each of the fiscal years ended March 31:

(a) For segment reporting purposes, long-lived assets include Investments in unconsolidated affiliates, Central parts and Property, plant and equipment.

21. SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION

Supplemental disclosures of cash flow information for the fiscal years ended March 31 were as follows:

22. SUBSEQUENT EVENTS

Dividends on Common Stock- Subsequent to the end of the quarter, the Company declared a quarterly cash dividend of $0.20 per share of common stock. The dividend is payable on June 15, 2026 to stockholders of record at the close of business on June 1, 2026.

Share Repurchase Program- Subsequent to the end of the fiscal year,0.6 million shares of common stock at a cost of $86.7 million were repurchased under the Board of Directors’ authorization.