Nature of Operations and Basis of Presentation	9 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations and Basis of Presentation Anterix Inc. (the “Company”) is the largest holder of licensed spectrum in the 900 MHz band (896-901/935-940 MHz) throughout the contiguous United States, plus Hawaii, Alaska and Puerto Rico. The Company’s mission is to transform how critical infrastructure stays connected. The Company is focused on commercializing its spectrum assets and expanding the advanced intelligent infrastructure solutions designed to enhance efficiency, strengthen resilience, and accelerate digital transformation to enable the Company’s targeted utility and critical infrastructure customers to deploy private broadband networks. Business Developments In November 2025, the Company and Crown Castle, one of the nation’s largest tower companies, announced a new turnkey tower service, TowerX, that helps utilities accelerate buildout timelines by providing access to pre-negotiated tower sites, centralized data and expert support. Additionally, the Company also relaunched CatalyX, a turnkey SIM provisioning, connectivity management and roaming solution that helps utilities efficiently and securely activate and manage devices across public and private networks. Basis of Presentation and Use of Estimates The consolidated financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Pursuant to the rules and regulations of the SEC, certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted, these unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2025, filed with the SEC on June 24, 2025 (the “2025 Annual Report”). In the Company’s opinion, all normal and recurring adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented have been included. The Company believes that the disclosures made in the unaudited consolidated interim financial statements are adequate to make the information not misleading. The results of operations for the interim periods presented are not necessarily indicative of the results for the year. The Company is also required to make certain estimates and assumptions that affect the reported amounts. These estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the financial statements in the applicable period. Accordingly, actual results could materially differ from those estimates. The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Recently Issued Accounting Pronouncements In December 2023, the Financial Accounting Standards Board, (“FASB”) issued Accounting Standards Updates (“ASU”) 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid and to improve the effectiveness of income tax disclosures. This update is effective for annual periods beginning after December 15, 2024. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures and subsequently amended with ASU 2025-01, which was issued in January 2025. This update requires public business entities to disclose, on an annual and interim basis, disaggregated information about certain income statement expense line items in the notes to the financial statements. This update is effective for annual periods beginning after December 15, 2026, and interim periods within annual periods beginning after December 15, 2027. Early adoption is permitted and should be applied either prospectively or retroactively. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures. In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements. This update improves the navigability and applicability of the required interim disclosures. This update provides additional guidance on what disclosures should be provided in interim reporting periods and requires public business entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. This update is effective for interim periods within annual periods beginning after December 15, 2027. Early adoption is permitted and should be applied either prospectively or retroactively. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures. In December 2025, the FASB issued ASU 2025-12, codification improvements. The amendments in this ASU include technical corrections and other amendments intended to clarify and improve the Accounting Standards Codification across various topics. The amendments related to Accounting Standards Codification, Earnings per Share (“ASC 260”) are required to be applied retrospectively, while all other amendments may be applied either prospectively or retrospectively. This update is effective for annual periods beginning after December 15, 2026, and interim periods within those annual periods. Early adoption is permitted and should be applied either prospectively or retroactively. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures.

Anterix Inc. (the “Company”) is the largest holder of licensed spectrum in the 900 MHz band (896-901/935-940 MHz) throughout the contiguous United States, plus Hawaii, Alaska and Puerto Rico. The Company’s mission is to transform how critical infrastructure stays connected. The Company is focused on commercializing its spectrum assets and expanding the advanced intelligent infrastructure solutions designed to enhance efficiency, strengthen resilience, and accelerate digital transformation to enable the Company’s targeted utility and critical infrastructure customers to deploy private broadband networks.

The consolidated financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Pursuant to the rules and regulations of the SEC, certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted, these unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2025, filed with the SEC on June 24, 2025 (the “2025 Annual Report”). In the Company’s opinion, all normal and recurring adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented have been included. The Company believes that the disclosures made in the unaudited consolidated interim financial statements are adequate to make the information not misleading. The results of operations for the interim periods presented are not necessarily indicative of the results for the year. The Company is also required to make certain estimates and assumptions that affect the reported amounts. These estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the financial statements in the applicable period. Accordingly, actual results could materially differ from those estimates.

In December 2023, the Financial Accounting Standards Board, (“FASB”) issued Accounting Standards Updates (“ASU”) 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid and to improve the effectiveness of income tax disclosures. This update is effective for annual periods beginning after December 15, 2024. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures and subsequently amended with ASU 2025-01, which was issued in January 2025. This update requires public business entities to disclose, on an annual and interim basis, disaggregated information about certain income statement expense line items in the notes to the financial statements. This update is effective for annual periods beginning after December 15, 2026, and interim periods within annual periods beginning after December 15, 2027. Early adoption is permitted and should be applied either prospectively or retroactively. The

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements. This update improves the navigability and applicability of the required interim disclosures. This update provides additional guidance on what disclosures should be provided in interim reporting periods and requires public business entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. This update is effective for interim periods within annual periods beginning after December 15, 2027. Early adoption is permitted and should be applied either prospectively or retroactively. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-12, codification improvements. The amendments in this ASU include technical corrections and other amendments intended to clarify and improve the Accounting Standards Codification across various topics. The amendments related to Accounting Standards Codification, Earnings per Share (“ASC 260”) are required to be applied retrospectively, while all other amendments may be applied either prospectively or retrospectively. This update is effective for annual periods beginning after December 15, 2026, and interim periods within those annual periods. Early adoption is permitted and should be applied either prospectively or retroactively. The Company is currently evaluating the impact of the new standard on the Company’s consolidated financial statements and related disclosures.