X0508 4 2025-11-03 0 0001003078 MSC INDUSTRIAL DIRECT CO INC MSM 0001923635 Shacklett Kimberly C/O MSC INDUSTRIAL DIRECT CO., INC. 515 BROADHOLLOW ROAD MELVILLE NY 11747 0 1 0 0 SVP, Customer Experience 0 Class A Common Stock, $0.001 par value 2025-11-03 4 M 0 511 0 A 15168 D Class A Common Stock, $0.001 par value 2025-11-03 4 M 0 40.824 0 A 15209 D Class A Common Stock, $0.001 par value 2025-11-03 4 F 0 157.824 84.79 D 15051 D Restricted Stock Units (RSU) 2025-11-03 4 A 0 2358 0 A Class A Common Stock, $0.001 par value 2358 2358 D Restricted Stock Units (RSU) 2025-11-03 4 M 0 511 0 D Class A Common Stock, $0.001 par value 511 1023 D Dividend Equivalent Units 2025-11-03 4 M 0 40.824 0 D Class A Common Stock, $0.001 par value 40.824 317 D Each RSU represents a contingent right to receive one share of Common Stock. The dividend equivalent units accrued with respect to outstanding awards of restricted stock units (RSUs) and vest at the same time(s) as the underlying RSUs. Each dividend equivalent unit represents a contingent right to receive one share of Common Stock. Disposition of Class A Common Stock to the Issuer to cover tax withholding obligations arising from the vesting of RSUs and DEUs. 2,358 RSUs were granted on November 3, 2025. 589 RSUs vest on each of November 3, 2026 and November 3, 2027, and 590 RSUs vest on each of November 3, 2028 and November 3, 2029, provided that the Reporting Person remains continuously employed by the Issuer through each applicable vesting date. The vested shares will be delivered to the Reporting Person upon vesting. 2,045 RSUs were granted on November 3, 2023. 511 RSUs vested on each of November 3, 2024 and November 3, 2025. 511 RSUs vest on November 3, 2026 and 512 RSUs vest on November 3, 2027, provided that the Reporting Person remains continuously employed by the Issuer through each applicable vesting date. The vested shares will be delivered to the Reporting Person upon vesting. Includes 51.717 dividend equivalent units accrued on November 27, 2024, 54.708 dividend equivalent units accrued on January 29, 2025, 59.017 dividend equivalent units accrued on April 23, 2025 and 51.921 dividend units accrued on July 23, 2025 with respect to outstanding awards of restricted stock units (RSUs). Such dividend equivalent units vest at the same time(s) as the underlying RSUs and represent a contingent right to receive one share of Common Stock. /s/ Kimberly Shacklett 2025-11-04