X0609 4 2026-04-28 0 0001953926 Zenas BioPharma, Inc. ZBIO 0001228865 MOULDER LEON O JR false C/O ZENAS BIOPHARMA, INC. 852 WINTER STREET, SUITE 250 WALTHAM MA 02451 1 1 0 0 Chief Executive Officer 0 Common Stock 2026-04-28 4 P 0 25000 18.02 A 1751039 I See Footnote Common Stock 2026-04-29 4 P 0 35000 17.62 A 1786039 I See Footnote Common Stock 36928 I See Footnote Common Stock 423155 D The price reported is a weighted average price. These shares were purchased in multiple transactions ranging from $17.87 to $18.05, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range. Leon O. Moulder, Jr. 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. Mr. Moulder is the Issuer's chief executive officer and Chairman of its board of directors. Mr. Moulder disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. The price reported is a weighted average price. These shares were purchased in multiple transactions ranging from $17.56 to $17.67, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range. The reporting person is a Trustee of the Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 (the "Trust") and may be deemed to have voting and dispositive power over the shares held by the Trust. The reporting person is the Issuer's chief executive officer and Chairman of its board of directors. The reporting person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. By: /s/ Chase Jayasekera, Attorney-in-Fact 2026-04-29