ZBIO insider update: SR One entities report $19 share purchases

Rhea-AI Filing Summary

Zenas BioPharma (ZBIO): Form 4 insider purchase — SR One–affiliated entities reported open-market acquisitions of common stock on October 9, 2025 at $19 per share. The filing lists two purchases: 63,158 shares and 63,157 shares, acquired pursuant to a Securities Purchase Agreement dated October 7, 2025.

Following these transactions, beneficial holdings reported include 1,173,395 shares (indirect, Note 2), 1,917,895 shares (indirect, Note 3), and 1,946,564 shares (indirect, Note 4). The reporting person is indicated as a Director and 10% Owner, with the form filed by more than one reporting person.

Insights

Equity ownership & insider transactions analyst

Insider-affiliated funds bought ZBIO shares at $19; neutral signal.

SR One–related entities disclosed purchases of Zenas BioPharma common stock on October 9, 2025 at $19 per share, executed under a securities purchase agreement dated October 7, 2025. The filing details two blocks of 63,158 and 63,157 shares and reports updated indirect beneficial holdings by separate SR One–affiliated funds.

Because this is a Form 4, it records ownership changes rather than operational performance. The entities disclaim beneficial ownership beyond pecuniary interest per footnotes, which is standard language for fund structures. Actual market impact depends on future ownership changes, which are not indicated here.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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X

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

1. Name and Address of Reporting Person^*

SR ONE CAPITAL MANAGEMENT, LLC

(Last) (First) (Middle)

985 OLD EAGLE SCHOOL ROAD

SUITE 511

(Street)

WAYNE PA 19087

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Zenas BioPharma, Inc. [ ZBIO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/09/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	10/09/2025		P(1)		63,158	A	$19	1,173,395	I	See Note 2(2)
Common Stock	10/09/2025		P(1)		63,157	A	$19	1,917,895	I	See Note 3(3)
Common Stock								1,946,564	I	See Note 4(4)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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

1. Name and Address of Reporting Person^*

SR ONE CAPITAL MANAGEMENT, LLC

(Last) (First) (Middle)

985 OLD EAGLE SCHOOL ROAD

SUITE 511

(Street)

WAYNE PA 19087

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

George Simeon

(Last) (First) (Middle)

985 OLD EAGLE SCHOOL ROAD

SUITE 511

(Street)

WAYNE PA 19087

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. Acquired from the Issuer on October 9, 2025 pursuant to a Securities Purchase Agreement dated October 7, 2025.

2. The reported securities are held directly by SR One Capital Opportunities Fund I, LP. SR One Capital Opportunities Partners I, LP is the general partner of SR One Capital Opportunities Fund I, LP, and SR One Capital Management, LLC is the general partner of SR One Capital Opportunities Partners I, LP. Simeon George, M.D. is the managing member of SR One Capital Management, LLC. Each of SR One Capital Opportunities Partners I, LP, SR One Capital Management, LLC and Dr. George may be deemed to have shared power to vote or dispose of these shares, and each disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein.

3. The reported securities are held directly by AMZL, LP. SR One Capital SMA Partners, LP is the general partner of AMZL, LP, and SR One Capital Management, LLC is the general partner of SR One Capital SMA Partners, LP. Simeon George, M.D. is the managing member of SR One Capital Management, LLC. Each of SR One Capital SMA Partners, LP, SR One Capital Management, LLC and Dr. George may be deemed to have shared power to vote or dispose of these shares, and each disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein.

4. The reported securities are held directly by SR One Capital Fund II Aggregator, LP. SR One Capital Partners II, LP is the general partner of SR One Capital Fund II Aggregator, LP, and SR One Capital Management, LLC is the general partner of SR One Capital Partners II, LP. Simeon George, M.D. is the managing member of SR One Capital Management, LLC. Each of SR One Capital Partners II, LP, SR One Capital Management, LLC and Dr. George may be deemed to have shared power to vote or dispose of these shares, and each disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein.

	/s/ Sasha Keough, attorney-in-fact for SR One Capital Management, LLC	10/14/2025
	/s/ Sasha Keough, attorney-in-fact for Simeon George	10/14/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What did ZBIO disclose in this Form 4?

SR One–affiliated entities acquired common stock on October 9, 2025 at $19 per share, under a Securities Purchase Agreement dated October 7, 2025.

How many ZBIO shares were bought in the reported transactions?

Two purchases were reported: 63,158 shares and 63,157 shares of common stock.

What are the updated beneficial holdings after the transactions?

Reported indirect holdings include 1,173,395 (Note 2), 1,917,895 (Note 3), and 1,946,564 (Note 4) shares.

Who is the reporting person and relationship to ZBIO?

The reporting person is indicated as a Director and 10% Owner, with the form filed by more than one reporting person.

Were the shares acquired from the market or the company?

The shares were acquired from the issuer pursuant to a Securities Purchase Agreement dated October 7, 2025.

Do the reporting entities claim full beneficial ownership?

Per footnotes, they may be deemed to share voting/dispositive power and disclaim beneficial ownership beyond any pecuniary interest.