X0609 4 2026-08-28 0000350894 SEI INVESTMENTS CO SEIC 0001745371 Peterson Michael false 1 FREEDOM VALLEY DRIVE OAKS PA 19456 true Executive Vice President false Common Stock 2026-08-28 4 M 0 37500 56.54 A 57648 D Common Stock 2026-08-28 4 S 0 37500 111.51 D 20148 D Common Stock 454 I By Employee Stock Purchase Plan Option to Purchase Common Stock 56.54 2026-08-28 4 M 0 37500 D 2024-12-31 2030-12-08 Common Stock 37500 0 D Represents the weighted average of a range of sale prices from $111.19 to $112.07. The reporting person undertakes to provide to the Staff of the Securities and Exchange Commission, the Company, or any stockholder of the Company, upon request, full information regarding the number of shares sold at each separate price. Reflects the addition of approximately 91 shares purchased by the Reporting Person through the Company's Employee Stock Purchase Plan. Received as employment compensation. /s/ Michael Peterson by Lindsay A. Barci, attorney in fact 2026-09-01