Sec Form 4 Filing - SUBIN NEIL S @ NEXTNAV INC. - 2026-06-22

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person SUBIN NEIL S 2. Issuer Name and Ticker or Trading Symbol NEXTNAV INC. [ NN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 11911 FREEDOM DR., STE. 200 3. Date of Earliest Transaction (MM/DD/YY) 06/22/2026 (Street) RESTON, VA20190 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 06/22/2026 C( 2 ) 502,707 ( 3 ) A $ 0 502,707 I Persian Road I, LP ( 1 ) Common Stock 06/23/2026 X( 5 ) 250,000 A $ 11.5 2,765,213 I MILFAM Investments LLC ( 4 ) Common Stock 168,892 ( 8 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares 5.00% Senior Secured Convertible Notes due 2028 $ 12.56 06/22/2026 C( 2 ) 502,707 ( 3 ) ( 2 ) ( 2 ) Common Stock 502,707 ( 3 ) $ 0 0 I Persian Road I, LP ( 1 ) Warrants $ 11.5 06/23/2026 X( 5 ) 250,000 ( 6 ) ( 7 ) Common Stock 250,000 $ 0 0 I MILFAM Investments LLC ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SUBIN NEIL S 11911 FREEDOM DR. STE. 200 RESTON, VA20190 X Signatures /s/ James S. Black, by power of attorney 06/24/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Reporting Person is Manager of MILFAM LLC. MILFAM LLC is the manager of MILFAM GP LLC, the general partner of Persian Road I, LP, a limited partnership ("Persian Road"). ( 2 )Pursuant to a Note Purchase Agreement with NextNav Inc. (the "Issuer"), dated March 12, 2025 (the "NPA"), Persian Road purchased $6,300,000 aggregate principal amount of the Issuer's 5.00% Senior Secured Convertible Notes due 2028 (the "2028 Notes"), at a price of 100% of the principal amount. The 2028 Notes are convertible, as of the date of issue on March 27, 2025, into the Issuer's shares of common stock, $0.0001 par value per share (the "Common Stock"), at a price of $12.56 per share. The 2028 Notes originally had a maturity date of June 30, 2028. On June 15, 2026, the Issuer elected to redeem all outstanding 2028 Notes pursuant to their terms, which accelerated the last date for their conversion to June 23, 2026. Persian Road converted the 2028 Notes prior to such redemption deadline. The Reporting Person disclaims any beneficial ownership of the reported securities other than to the extent of any pecuniary interest he may have therein, directly or indirectly. ( 3 )The Reporting Person previously reported beneficial ownership of 2028 Notes representing the number of shares into which the principal amount was convertible. At the time of conversion, the 2028 Notes converted into 502,707 shares of Common Stock, consisting of 501,592 shares attributable to outstanding principal and the remaining shares attributable to accrued but unpaid interest. Accordingly, the number of shares of Common Stock acquired upon conversion exceeds the number of shares initially reported as underlying the 2028 Notes. ( 4 )The Reporting Person is the Manager of MILFAM LLC. MILFAM LLC is the manager of MILFAM Investments LLC ("MILFAM Investments"). The Reporting Person disclaims any beneficial ownership of the reported securities other than to the extent of any pecuniary interest he may have therein, directly or indirectly. ( 5 )Represents the cash exercise of 250,000 warrants (the "Public Warrants") to purchase shares of the Issuer's Common Stock at an exercise price of $11.50 per share, pursuant to the terms of the Amended and Restated Warrant Agreement, dated as of October 28, 2021 (the "Warrant Agreement"), by and among Spartacus Acquisition Corporation, the Issuer, and Continental Stock Transfer & Trust Company, as warrant agent. MILFAM Investments paid the aggregate exercise price in cash and received 250,000 shares of Common Stock upon exercise. No separate consideration was received for the Public Warrants upon exercise. ( 6 )The Public Warrants became exercisable 30 days after the completion of the Issuer's initial business combination, which closed on October 28, 2021 (the "Business Combination"). ( 7 )The Public Warrants originally had an expiration date five years after the completion of the Business Combination. On May 27, 2026, the Issuer announced that it elected to redeem all outstanding Public Warrants, and set a redemption date of June 26, 2026 (the "Redemption Date"). Holders of Public Warrants may exercise their Public Warrants for cash at the exercise price at any time prior to 5:00 p.m. New York City time on the Redemption Date, in accordance with the terms of the Warrant Agreement. MILFAM Investments exercised the Public Warrants prior to such redemption deadline. ( 8 )Includes 7,550 restricted shares, 100% of which will vest on May 1, 2027, subject to the Reporting Person's continued service through the applicable vesting date.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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