SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)

NEXTNAV INC.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

65345N106

(CUSIP Number)

Neil S. Subin
2366 SE Ocean Blvd, Suite 400,
Stuart, FL, 34996
(561) 287-5399

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

05/22/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. Checkbox not checked

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP Number(s):

65345N106

Name of reporting person

SUBIN NEIL S

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

AF, OO

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 180,523.00
8	Shared Voting Power 3,266,805.00
9	Sole Dispositive Power 180,523.00
10	Shared Dispositive Power 3,266,805.00

Aggregate amount beneficially owned by each reporting person

3,447,328.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

2.5 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

Note to Rows 7, 9 and 11: Includes 11,631 shares of common stock, par value $0.0001 per share ("Common Stock"), of NextNav Inc. (the "Issuer") held by Sufam Advisors Corp. ("SAC"), which is 100% owned by SF Nevis Investco LLC ("Nevis"). Mr. Subin manages Nevis. Mr. Subin disclaims any beneficial ownership of the securities owned by SAC other than to the extent of any pecuniary interest he may have therein, directly or indirectly. Note to Rows 8, 10 and 11: Represents 2,515,213 shares of Common Stock held by MILFAM Investments LLC ("Milfam Investments") and 250,000 warrants held by Milfam Investments that are exercisable for 250,000 shares of Common Stock (the "Warrant Shares"). Mr. Subin is the President and Manager of MILFAM LLC, which serves as manager of Milfam Investments, consequently, he may be deemed to share beneficial ownership of the shares of Common Stock held by Milfam Investments. Also, represents 501,592 shares of Common Stock (the "Note Shares"), which are convertible from 5.00% Senior Secured Convertible Notes due 2028, held by Persian Road I, LP ("Persian Road"). Mr. Subin manages Persian Road. Mr. Subin disclaims any beneficial ownership of the reported shares other than to the extent of any pecuniary interest he may have therein, directly or indirectly. Note to Row 13: The percentages reported in this Amendment No. 1 to Schedule 13D (this "Amendment") are based upon the deemed to be outstanding shares of Common Stock pursuant to Rule 13d-3(d)(1) of the Securities Exchange Act of 1934, as amended ("Rule 13d-3(d)(1)"), which includes (i) 136,436,939 shares of Common Stock outstanding as of May 11, 2026 (according to the Issuer's Quarterly Report on Form 10-Q filed with the U.S. Securities and Exchange Commission on May 14, 2026 (the "Form 10-Q") plus (ii) the Warrant Shares, plus (iii) the Note Shares, although the Warrant Shares and Note Shares are not deemed to be outstanding for the purpose of computing the percentage of the class owned by any other person besides Mr. Subin. Mr. Subin has ceased to be the beneficial owner of more than five percent of Common Stock and, as such, this Amendment constitutes an exit filing for Mr. Subin.

SCHEDULE 13D

CUSIP Number(s):

65345N106

Name of reporting person

Milfam CI LLC Spartacus

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 5,488,884.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 5,488,884.00

Aggregate amount beneficially owned by each reporting person

5,488,884.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

3.9 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

Note to Rows 8, 10 and 11: Represents 1,948,907 shares of Common Stock held by MILFAM CI LLC SPARTACUS ("CI Spartacus") and 3,539,977 warrants held by CI Spartacus that are exercisable for 3,539,977 shares of Common Stock ("CI Spartacus Warrant Shares"). Note to Row 13: The percentages reported in this Amendment are based upon the deemed to be outstanding shares of Common Stock pursuant to Rule 13d-3(d)(1), which includes (i) 136,436,939 shares of Common Stock outstanding as of May 11, 2026 (according to the Form 10-Q) plus (ii) the CI Spartacus Warrant Shares, although the CI Spartacus Warrant Shares are not deemed to be outstanding for the purpose of computing the percentage of the class owned by any other person besides CI Spartacus. CI Spartacus has ceased to be the beneficial owner of more than five percent of Common Stock and, as such, this Amendment constitutes an exit filing for CI Spartacus.

SCHEDULE 13D

CUSIP Number(s):

65345N106

Name of reporting person

MILFAM CI Management LLC

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

AF, OO

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

Aggregate amount beneficially owned by each reporting person

0.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

0.0 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

Note to Row 13: MILFAM CI Management LLC ("CI Management") has ceased to be the beneficial owner of more than five percent of Common Stock and, as such, this Amendment constitutes an exit filing for CI Management.

SCHEDULE 13D

Item 1.

Security and Issuer

(a)

Title of Class of Securities:

Common Stock, par value $0.0001 per share

(b)

Name of Issuer:

NEXTNAV INC.

(c)

Address of Issuer's Principal Executive Offices:

11911 Freedom Dr., Suite 200, Reston, VIRGINIA , 20190.

Item 1 Comment:

This Amendment is filed with the SEC on behalf of (i) Mr. Subin, (ii) CI Spartacus, and (iii) CI Management (each person and entity named in items (i) through (iii), collectively, the "Reporting Persons") relating to Common Stock. This Amendment amends and supplements the Schedule 13D originally filed by the Reporting Persons with the SEC on August 19, 2022 (the "Schedule 13D"). Except as specifically provided herein, this Amendment does not modify any of the information previously reported in the Schedule 13D. Capitalized terms used but not defined in this Amendment shall have the same meanings ascribed to them in the Schedule 13D.

Item 5.

Interest in Securities of the Issuer

(a)

See rows (11) and (13) of the cover pages to this Amendment for the aggregate number of shares of Common Stock and percentages of the shares of Common Stock beneficially owned by each Reporting Person. The percentage reported in this Amendment is based upon 136,439,939 shares of Common Stock outstanding as of May 11, 2026 (according to the Form 10-Q).

(b)

See rows (7) through (10) of the cover pages to this Amendment 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.

(c)

The following transactions were effected in the sixty days prior to the date of this Amendment involving the Reporting Persons: N/A

(d)

N/A

(e)

May 22, 2026

Item 6.

Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer

On May 22, 2026, CI Spartacus entered into a Portfolio Management Agreement (the "PMA") with Warberg Asset Management LLC (the "Portfolio Manager"), pursuant to which CI Spartacus appointed the Portfolio Manager as its investment advisor with sole and exclusive discretionary trading authority over securities held by CI Spartacus. As a result of the PMA, neither CI Management nor Mr. Subin, through his ownership and control of CI Management, retains beneficial ownership of the securities held by CI Spartacus, and each Reporting Person has accordingly ceased to be the beneficial owner of more than five percent of the Common Stock.

Item 7.

Material to be Filed as Exhibits.

Exhibit 1 - Portfolio Management Agreement, dated May 22, 2026, by and between Warberg Asset Management LLC and MILFAM CI LLC SPARTACUS. (Schedules and exhibits have been omitted as they are not material. They will be furnished supplementally to the SEC upon request.)

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

SUBIN NEIL S

Signature:	/s/ Neil S. Subin
Name/Title:	Neil S. Subin
Date:	05/22/2026

Milfam CI LLC Spartacus

Signature:	/s/ Neil S. Subin
Name/Title:	Neil S. Subin/Sole Member of Milfam CI Management LLC, Manager of Milfam CI LLC Spartacus
Date:	05/22/2026

MILFAM CI Management LLC

Signature:	/s/ Neil S. Subin
Name/Title:	Neil S. Subin/Sole Member
Date:	05/22/2026

Amendment: SEC Form SCHEDULE 13D/A filed by NextNav Inc.