X0609 4 2026-04-07 0 0001846253 OmniAb, Inc. OABI 0001462354 GUSTAFSON KURT A false 5980 HORTON STREET, STE 600 EMERYVILLE CA 94608 0 1 0 0 Executive VP, Finance and CFO 0 Common Stock 2026-04-07 4 M 0 13542 0 A 268396 D Common Stock 2026-04-07 4 S 0 6913 1.49 D 261483 D Restricted Stock Units 0 2026-04-07 4 M 0 13542 0 D Common Stock 13542 111042 D Represents the vesting of an RSU grant which occurs in three substantially equal annual installments beginning on April 7, 2024. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock. The total includes the transfer of 13,997 OABI common stock shares on March 11, 2026 to the reporting person's ex-spouse per a domestic relations order. Represents the number of shares required to be sold by the reporting person to cover tax withholding obligations in connection with the vesting of RSUs. These sales are mandated by the Issuer's election under its equity incentive plans to require the satisfaction of a tax withholding obligation to be funded by a "sell-to-cover" transaction and do not represent discretionary trades by the reporting person. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.46 to $1.53. 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 sold at each separate price within the range set forth in this footnote. By: /s/ Charles S. Berkman, Attorney-in-Fact For: Kurt A. Gustafson 2026-04-07