X0202 SCHEDULE 13D/A 0000902664-24-006867 0001313756 XXXXXXXX LIVE 8 Common Stock, par value $0.0001 per share 06/25/2026 true 0001304492 03676C100 Anterix Inc.

3 GARRET MOUNTAIN PLAZA SUITE 401 WOODLAND PARK NJ 07424

Ele Klein 212-756-2000 McDermott Will & Schulte LLP 919 Third Avenue New York NY 10022 0001313756 N Owl Creek Asset Management, L.P. b AF N DE 0.00 5411776.00 0.00 5411776.00 5411776.00 N 27.7 PN 0001269751 N Jeffrey A. Altman b AF N X1 139908.00 5411776.00 139908.00 5411776.00 5551684.00 N 28.5 IN Note to rows (7)(9)(11)(13): Includes a total of (i) 15,416 vested and unvested restricted stock awards held by Mr. Altman and (ii) 124,492 shares of Common Stock directly held by Mr. Altman. Common Stock, par value $0.0001 per share Anterix Inc. 3 GARRET MOUNTAIN PLAZA SUITE 401 WOODLAND PARK NJ 07424 The following constitutes Amendment No. 8 to the Schedule 13D ("Amendment No. 8"). This Amendment No. 8 amends the Schedule 13D as specifically set forth herein. Capitalized terms used herein and not otherwise defined in this Amendment No. 8 have the meanings set forth in the Schedule 13D. This Amendment No. 8 amends Items 3 and 5(a)-(c) as set forth below. This Amendment No. 8 is being filed to report a decrease in the percentage of the shares of Common Stock beneficially owned by the Reporting Persons, which decrease resulted solely from an increase in the number of outstanding shares of Common Stock reported by the Issuer. Item 3 is hereby amended and restated in its entirety as follows: Mr. Altman holds a total of 15,416 vested and unvested restricted stock awards received in consideration for his services on the board of directors of the Issuer. Mr. Altman may be deemed to hold his stock awards for the benefit of the Owl Creek Funds. Item 5(a) is hereby amended and restated in its entirety as follows: See rows (11) and (13) of the cover pages to this Schedule 13D for the aggregate number of shares of Common Stock and percentages of the shares of Common Stock beneficially owned by each of the Reporting Persons. The number of shares of Common Stock beneficially owned by the Reporting Persons is unchanged since the Reporting Persons' most recent filing on Form 4, filed with the Securities and Exchange Commission on August 7, 2025. The decrease in the percentage of the shares of Common Stock beneficially owned by the Reporting Persons resulted solely from an increase in the number of outstanding shares of Common Stock reported by the Issuer. The percentages used in this Schedule 13D are calculated based upon 19,506,240 shares of Common Stock outstanding, which is the sum of (i) 19,498,473 shares of Common Stock outstanding as of June 19, 2026, as reported in the Issuer's Annual Report on Form 10-K for the fiscal year ended March 31, 2026, filed with the Securities and Exchange Commission on June 25, 2026 and (ii) 7,767 shares of Common Stock underlying the unvested restricted stock awards reported herein. Item 5(b) is hereby amended and restated in its entirety as follows: See rows (7) through (10) of the cover pages to this Schedule 13D for the number of shares of Common Stock as to which each Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition. Item 5(c) is hereby amended and restated in its entirety as follows: No transactions in the shares of Common Stock have been effected by the Reporting Persons during the past sixty (60) days. Owl Creek Asset Management, L.P. /s/ Jeffrey A. Altman 07/08/2026 Jeffrey A. Altman /s/ Jeffrey A. Altman 07/08/2026