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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

X0202 SCHEDULE 13D/A 0001228865 XXXXXXXX LIVE 1 Common Stock, $0.0001 par value per share 03/31/2026 false 0001953926 98937L105 Zenas BioPharma, Inc. 852 Winter Street Suite 250 Waltham MA 02451 Leon O. Moulder, Jr. 857-271-2954 c/o Zenas BioPharma, Inc. 852 Winter Street, Suite 250 Waltham MA 02451 0001228865 N Leon O. Moulder, Jr. b AF N X1 1266954.00 1762967.00 1266954.00 1762967.00 3029921.00 N 4.794 IN (1) Rows 7 & 9: Consists of (i) 423,155 shares of common stock held directly by Mr. Moulder, and (ii) 843,799 shares of common stock underlying outstanding stock options exercisable within 60 days of the date of March 31, 2026. (2) Rows 8 & 10: Consists of (i) 1,726,039 shares of common stock held by Tellus BioVentures, LLC ("Tellus") and (ii) 36,928 shares of common stock held by Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 (the "Trust"). Mr. Moulder is the Managing Member of Tellus and may be deemed to have sole voting and dispositive power over the shares held by Tellus, and Mr. Moulder is a trustee of the Trust and may be deemed to have sole voting and dispositive power of the shares held by the Trust. (3) Row 11: Consists of (i) 423,155 shares of common stock held directly by Mr. Moulder, (ii) 843,799 shares of common stock underlying outstanding stock options exercisable within 60 days of March 31, 2026, (iii) 1,726,039 shares of common stock held by Tellus and (iv) 36,928 shares of common stock held by the Trust. Mr. Moulder is the Managing Member of Tellus and may be deemed to have sole voting and dispositive power over the shares held by Tellus, and Mr. Moulder is a trustee of the Trust and may be deemed to have sole voting and dispositive power of the shares held by the Trust. (4) Row 13: Calculated based on 57,361,260 shares of Common Stock outstanding, as reported by the Issuer in its Annual Report on Form 10-K for the year ended December 31, 2025, as filed with the Securities and Exchange Commission (the "Commission") on March 16, 2026 (the "2025 10-K"), plus (i) 5,000,000 shares of common stock issued by the Issuer in a registered public offering on March 31, 2026 (the "Equity Offering Shares"), as reported by the Issuer in its Current Report on Form 8-K filed with the Commission on March 31, 2026 and (ii) the 843,799 shares of common stock issuable upon the exercise of the options held by Mr. Moulder that are exercisable within 60 days of March 31, 2026. Y Tellus BioVentures, LLC b WC N DE 0.00 1726039.00 0.00 1726039.00 1726039.00 N 2.77 OO (1) Rows 8, 10 & 11: Consists of 1,726,039 shares of common stock held of record by Tellus. Mr. Moulder is the Managing Member of Tellus and may be deemed to have sole voting and dispositive power over the shares held by Tellus. (2) Row 13: Calculated based on 57,361,260 shares of Common Stock outstanding, as reported by the Issuer in the 2025 10-K, plus the Equity Offering Shares. Y Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 b AF N FL 0.00 36928.00 0.00 36928.00 36928.00 N 0.06 OO (1) Rows 8, 10 & 11: Consists of 36,928 shares of common stock held of record by Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 (the "Trust"). Mr. Moulder is a Trustee of the Trust and may be deemed to have sole voting and dispositive power over the shares held by the Trust. (2) Row 13: Calculated based on 57,361,260 shares of Common Stock outstanding, as reported by the Issuer in the 2025 10-K, plus the Equity Offering Shares. Common Stock, $0.0001 par value per share Zenas BioPharma, Inc. 852 Winter Street Suite 250 Waltham MA 02451 This Amendment No. 1 (this "Amendment") amends and supplements the Schedule 13D initially filed by Mr. Moulder, Tellus and the Trust on January 14, 2026 (the "Original Schedule 13D"). Only those items that are hereby reported are amended; all other items reported in the Original Schedule 13D remain unchanged. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable. Capitalized terms not defined in this Amendment have the meanings ascribed to them in the Original Schedule 13D. This Amendment is filed with respect to the Common Stock, par value $0.0001 per share ("Common Stock"), of Zenas BioPharma, Inc., a Delaware corporation (the "Issuer"). The address of the principal executive offices of the Issuer is 852 Winter Street, Suite 250, Waltham, MA 02451. Item 3 of the Original Schedule 13D is hereby amended and supplemented by adding the following to the end of Item 3: On February 2, 2026, Mr. Moulder purchased 57,000 shares of Common Stock in multiple open-market transactions at prices per share ranging from $17.69 to $18.14, inclusive. Between March 30, 2026 and March 31, 2026, Tellus purchased 54,000 shares of Common Stock in multiple open-market transactions at prices per share ranging from $18.195 to $19.58, inclusive. See Items 7-11 of the cover pages of this Statement. See Items 7-11 of the cover pages of this Statement. Except as reported in this Statement, no Reporting Person has effected any transactions in the Issuer's securities within the past 60 days. Not applicable. March 31, 2026 Leon O. Moulder, Jr. /s/ Leon O. Moulder, Jr. Leon O. Moulder, Jr. 04/02/2026 Tellus BioVentures, LLC /s / Leon O. Moulder, Jr. Leon O. Moulder, Jr., Managing Member 04/02/2026 Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 /s / Leon O. Moulder, Jr. Leon O. Moulder, Jr., Trustee 04/02/2026