SEC Filing | Zenas BioPharma, Inc

SCHEDULE 13D

CUSIP No.

Name of reporting person

SR One Capital Management, LLC

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 5,037,854.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 5,037,854.00

Aggregate amount beneficially owned by each reporting person

5,037,854.00

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)

7.7 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

SR One Capital Fund II Aggregator, LP

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 1,946,564.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,946,564.00

Aggregate amount beneficially owned by each reporting person

1,946,564.00

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)

3.0 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

SR One Capital Partners II, LP

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 1,946,564.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,946,564.00

Aggregate amount beneficially owned by each reporting person

1,946,564.00

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)

3.0 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

AMZL, LP

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 1,917,895.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,917,895.00

Aggregate amount beneficially owned by each reporting person

1,917,895.00

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)

2.9 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

SR One Capital SMA Partners, LP

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 1,917,895.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,917,895.00

Aggregate amount beneficially owned by each reporting person

1,917,895.00

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)

2.9 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

SR One Capital Opportunities Fund I, LP

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 1,173,395.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,173,395.00

Aggregate amount beneficially owned by each reporting person

1,173,395.00

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)

1.8 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

SR One Capital Opportunities Partners I, LP

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 1,173,395.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,173,395.00

Aggregate amount beneficially owned by each reporting person

1,173,395.00

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)

1.8 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

Name of reporting person

Simeon George

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 5,037,854.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 5,037,854.00

Aggregate amount beneficially owned by each reporting person

5,037,854.00

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)

7.7 %

Type of Reporting Person (See Instructions)

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:

Zenas BioPharma, Inc.

(c)

Address of Issuer's Principal Executive Offices:

852 Winter Street, Suite 250, Waltham, MASSACHUSETTS , 02451.

Item 1 Comment:

This Amendment No. 2 ("Amendment No. 2") to Schedule 13D amends and supplements the statement on Schedule 13D originally filed on September 23, 2024 (the "Schedule 13D") and Amendment No. 1 thereto filed on October 14, 2025 ("Amendment No. 1") relating to the Common Stock of the Issuer. Certain terms used but not defined in this Amendment No. 2 have the meanings assigned thereto in the Schedule 13D (and Amendment No. 1 thereto). Except as specifically provided herein, this Amendment No. 2 does not modify any of the information previously reported on the Schedule 13D (and Amendment No. 1 thereto). This Amendment No. 2 is being filed to report that the beneficial ownership of Common Stock by the Reporting Persons (as defined below) has decreased by more than 1% as a result of an increase in the number of Common Stock outstanding.

Item 2.

Identity and Background

(a)

SR One Capital Management, LLC ("SR One Capital Management"); SR One Capital Fund II Aggregator, LP ("SR One Fund II Aggregator"); SR One Capital Partners II, LP ("SR One Partners II"); AMZL, LP ("AMZL"); SR One Capital SMA Partners, LP ("SMA Partners"); SR One Capital Opportunities Fund I, LP ("SR One Opportunities Fund I"); SR One Capital Opportunities Partners I, LP ("SR One Opportunities Partners I"); and Simeon George, M.D. ("Dr. George"). SR One Fund II Aggregator is directly controlled by its general partner, SR One Partners II. AMZL is directly controlled by its general partner, SMA Partners. SR One Opportunities Fund I is directly controlled by its general partner, SR One Opportunities Partners I. SR One Partners II, SMA Partners and SR One Opportunities Partners I are directly controlled by their general partners, SR One Capital Management, and Dr. George controls SR One Capital Management. Accordingly, each of SR One Capital Management and Dr. George may be deemed to have voting and dispositive power with respect to the SR One Fund II Aggregator Shares, the AMZL Shares and the SR One Opportunities Fund I Shares (each as defined below). The persons named in this Item 2 are referred to individually herein as a "Reporting Person" and collectively as the "Reporting Persons." SR One Fund II Aggregator, AMZL and SR One Opportunities Fund I are referred to collectively as the "Funds."

(b)

The address of each Reporting Person for purposes of this filing is c/o SR One Capital Management, LP, 929 Main Street, Suite 200, Redwood City, CA 94063.

(c)

The principal business of the Funds is to invest in and assist growth-oriented businesses. The principal business of SR One Partners II is to act as the sole general partner of SR One Fund II Aggregator. The principal business of SMA Partners is to act as the sole general partner of AMZL. The principal business of SR One Opportunities Partners I is to act as the sole general partner of SR One Opportunities Fund I. The principal business of SR One Capital Management is to act as the sole general partner of SR One Partners II, SMA Partners, SR One Opportunities Partners I and a number of affiliated partnerships with similar businesses. The principal business of Dr. George is to manage SR One Capital Management.

(d)

During the five years prior to the date hereof, none of the Reporting Persons has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(e)

(f)

SR One Fund II Aggregator, SR One Partners II, AMZL, SMA Partners, SR One Opportunities Fund I, and SR One Opportunities Partners I are limited partnerships organized under the laws of the State of Delaware. SR One Capital Management is a limited liability company organized under the laws of the State of Delaware. Dr. George is a United States citizen.

Item 3.

Source and Amount of Funds or Other Consideration

Not applicable.

Item 4.

Purpose of Transaction

Not applicable.

Item 5.

Interest in Securities of the Issuer

(a)

The percentage of outstanding shares of Common Stock which may be deemed to be beneficially owned by each Reporting Person is set forth on Line 13 of such Reporting Person's cover sheet. Such percentage was calculated based on 65,176,723 shares of Common Stock reported by the Issuer to be outstanding as of July 31, 2026, on the Issuer's Form 10-Q filed with the Securities Exchange Commission on August 13, 2026.

(b)

Regarding the number of shares as to which such person has: (i) sole power to vote or to direct the vote: See line 7 of cover sheets (ii) shared power to vote or to direct the vote: See line 8 of cover sheets (iii) sole power to dispose or to direct the disposition: See line 9 of cover sheets (iv) shared power to dispose or to direct the disposition: See line 10 of cover sheets

(c)

None of the Reporting Persons has effected any transaction in shares of Common Stock during the last 60 days.

(d)

No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, Common Stock beneficially owned by any of the Reporting Persons.

(e)

Not applicable.

Item 6.

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

Not applicable.

Item 7.

Material to be Filed as Exhibits.

Exhibit 1 - Agreement regarding filing of joint Schedule 13D. Exhibit 2 - Power of Attorney regarding filings under the Securities Exchange Act of 1934, as amended.

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.

SR One Capital Management, LLC

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

SR One Capital Fund II Aggregator, LP

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

SR One Capital Partners II, LP

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

AMZL, LP

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

SR One Capital SMA Partners, LP

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

SR One Capital Opportunities Fund I, LP

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

SR One Capital Opportunities Partners I, LP

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D., Managing Member
Date:	08/17/2026

Simeon George

Signature:	/s/ Sasha Keough
Name/Title:	Sasha Keough, as attorney-in-fact for Simeon George, M.D.
Date:	08/17/2026

Comments accompanying signature:

This Amendment No. 2 to Schedule 13D was executed by Sasha Keough on behalf of the individuals listed above pursuant to a Power of Attorney, a copy of which is attached as Exhibit 2.

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13D need be filed with respect to the ownership by each of the undersigned of shares of stock of Zenas BioPharma, Inc.

*/s/ Sasha Keough                          

This Agreement relating to Schedule 13D was executed by Sasha Keough on behalf of the individuals listed above pursuant to a Power of Attorney, a copy of which is attached hereto as Exhibit 2.

Know all by these presents, that the undersigned hereby makes, constitutes and appoints Sasha Keough, Karen Narolewski-Engel, James Macadam, and Alexander M. Bowling, and each of them singly, as each of the undersigned’s true and lawful attorneys-in-fact with full power and authority as hereinafter described to:

1. execute for and on behalf of each of the undersigned individual and entities (each, a “Filer” and collectively, the “Filers”) (i) Forms 3, 4, and 5 (including amendments thereto) in accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules thereunder, (ii) Form 144 in accordance with Rule 144 under the Securities Act of 1933, as amended (the “Securities Act”), and (iii) Schedules 13D and 13G (including amendments thereto) in accordance with Sections 13(d) and 13(g) of the Exchange Act and the rules thereunder;

2. do and perform any and all acts for and on behalf of each of the Filers which may be necessary or desirable to complete and execute any such Form 3, 4, or 5 (including amendments thereto), Form 144, or Schedule 13D or 13G (including amendments thereto) and timely file such form with the United States Securities and Exchange Commission (the “SEC”) and any stock exchange or similar authority, including, but not limited to, executing a Form ID or Update Passphrase request for and on behalf of each of the undersigned and filing such applications with the SEC; and

3. take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, a Filer, it being understood that the documents executed by such attorney-in-fact on behalf of such Filer pursuant to this Limited Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact’s discretion.

Each of the Filers hereby grants to each attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes a Filer might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all the acts such attorney-in-fact, or such attorney-in-fact’s substitute or substitutes, shall lawfully do or cause to be done by virtue of this Limited Power of Attorney and the rights and powers herein granted. Each of the Filers acknowledges that each of the foregoing attorneys-in-fact, in serving in such capacity at the request of such Filer, is not assuming any of such Filer’s responsibilities to comply with Sections 13 or 16 of the Exchange Act or Rule 144 under the Securities Act.

This Limited Power of Attorney shall remain in full force and effect until a Filer is no longer required to file Forms 3, 4, and 5 (including amendments thereto), Form 144, and Schedules 13D and 13G (including amendments thereto) with respect to such Filer’s holdings of and transactions in securities, unless earlier revoked by such Filer in a signed writing delivered to each of the foregoing attorneys-in-fact. In addition, at such time as any attorney-in-fact resigns as attorney-in-fact by the execution of a written resignation delivered to each Filer, without any action on the part of the Filers, this Limited Power of Attorney shall be partially revoked solely with respect to such individual; such individual shall cease to be an attorney-in-fact under this Limited Power of Attorney; and the authority of the other attorneys-in-fact then existing hereunder shall remain in full force and effect.

IN WITNESS WHEREOF, each of the undersigned has caused this Limited Power of Attorney to be executed as of this 12th day of December, 2022.

/s/ Simeon George                                                  

By:      /s/ Simeon George                                      

SR ONE CAPITAL MANAGEMENT, LLC

	By:                                 *
	Simeon George, M.D.
	Managing Member