POWELL INDUSTRIES INC (POWL) 4: 599 shares withheld for tax (Oct 2, 2026)

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-09-30 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: POWELL INDUSTRIES INC (POWL) CIK: 0000080420 --- Reporting Owner --- Name: Birchall John CIK: 0002025235 Role: Officer (Managing Director) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-09-30 | Code: F (Payment of exercise/tax) Shares: -599 | Price: $187.67 Total Value: $112,414.33 Shares Owned After: 19,102 | Ownership: D (Direct) Footnotes: [F1] Represents the average of the high and low stock price on 09/30/2026. [F2] Includes shares that have a time-based vesting provision. [Transaction #2] Security: Common Stock Date: 2026-10-01 | Code: A (Grant or award) Shares: +400 | Price: $181.67 Total Value: $72,668.00 Shares Owned After: 19,502 | Ownership: D (Direct) Footnotes: [F3] Represents the average closing stock price from September 1, 2026 - September 30, 2026. [F2] Includes shares that have a time-based vesting provision. [F4] The reported number of shares have been adjusted to reflect the impact of the issuer's 3-for-1 forward split of its Common Stock effected on April 2, 2026. --- Footnotes (Complete Index) --- F1: Represents the average of the high and low stock price on 09/30/2026. F2: Includes shares that have a time-based vesting provision. F3: Represents the average closing stock price from September 1, 2026 - September 30, 2026. F4: The reported number of shares have been adjusted to reflect the impact of the issuer's 3-for-1 forward split of its Common Stock effected on April 2, 2026. --- Signature --- /s/ Michael W. Metcalf, Power of Attorney for John Birchall (2026-10-02)