Sec Form 3 Filing - MOULDER LEON O JR @ Zenas BioPharma, Inc. - 2024-09-12

FORM 3 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 MOULDER LEON O JR 2. Issuer Name and Ticker or Trading Symbol Zenas BioPharma, Inc. [ ZBIO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) C/O ZENAS BIOPHARMA, INC., 1000 WINTER STREET, SUITE 1200 3. Date of Earliest Transaction (MM/DD/YY) 09/12/2024 (Street) WALTHAM, MA02451 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 1,115,499 I See Footnote ( 1 ) Common Stock 4,520 ( 2 ) 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 Series Seed Convertible Preferred Stock ( 3 ) < /td> ( 3 ) ( 3 ) Common Stock 164,523 I See Footnote ( 1 ) Series A Convertible Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 108,381 D Series B Convertible Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 372,017 I See Footnote ( 1 ) Series B Convertible Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 48,254 D Stock Option (Right to Buy) $ 9.3 ( 6 ) 07/17/2033 Common Stock 308,069 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other MOULDER LEON O JR C/O ZENAS BIOPHARMA, INC. 1000 WINTER STREET, SUITE 1200 WALTHAM, MA02451 X Chief Executive Officer Signatures By: /s/ Chase Jayasekera, Attorney-in-Fact 09/12/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Reporting Person is the Managing Member of Tellus BioVentures LLC ("Tellus") and may be deemed to have sole voting and dispositive power over the shares held by Tellus. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. ( 2 )Includes 753 shares of Common Stock, representing the unvested portion of an award of shares subject to certain restrictions for the purchase of 4,520 shares of Common Stock granted on August 21, 2020, which restrictions lapsed as to 25% of the shares on August 3, 2021, with the restrictions lapsing as to the remaining 75% of the shares in substantially equal installments over the following 36 months, subject to continued service. ( 3 )Each share of Series Seed Convertible Preferred Stock is convertible into shares of the Issuer's Common Stock on a 8.6831-for-1 basis and has no expiration date. The Series Seed Convertible Preferred Stock will automatically convert into Common Stock upon the closing of the Company's initial public offering. ( 4 )Each share of Series A Convertible Preferred Stock is convertible into shares of the Issuer's Common Stock on a 8.6831-for-1 basis and has no expiration date. The Series A Convertible Preferred Stock will automatically convert into Common Stock upon the closing of the Company's initial public offering. ( 5 )Each share of Series B Convertible Preferred Stock is convertible into shares of the Issuer's Common Stock on a 8.6831-for-1 basis and has no expiration date. The Series B Convertible Preferred Stock will automatically convert into Common Stock upon the closing of the Company's initial public offering. ( 6 )The option vested as to 25% of the underlying shares of common stock on June 29, 2024, the first anniversary of the vesting commencement date, and as to the remaining shares in equal month installments over 36 months thereafter, subject to continued service.

Remarks: Exhibit List: Exhibit 24 - Power of Attorney

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