X0202 SCHEDULE 13G/A 0000945621-24-000865 0001538449 XXXXXXXX LIVE 2 Common Stock 03/31/2026 0000902791 Barrett Business Services Inc 068463108 8100 NE Parkway Drive, Suite 200 Vancouver WA 98662 Rule 13d-1(b) Mawer Investment Management Ltd. A0 1701812 0 1701812 0 1701812 N 6.75 IA Based upon 25,203,090 Common Stock of Barrett Business Services Inc. (the "Issuer") outstanding as of February 11, 2026, as reported in the Issuer's 10-K filed with the Securities and Exchange Commission on February 26, 2026. Barrett Business Services Inc 8100 NE Parkway Drive, Suite 200, Vancouver, Washington, 98662 Mawer Investment Management Ltd. 600, 517 - 10th Avenue SW Calgary, Alberta, Canada T2R 0A8 Canada N IA 1,701,812 6.75% 1,701,812 0 1,701,812 0 Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Mawer Investment Management Ltd. /s/ John Wilson 05/01/2026