X0508 4 2026-02-24 0 0000080420 POWELL INDUSTRIES INC POWL 0001219199 POWELL THOMAS W P.O. BOX 300 GIDDINGS TX 78942 0 0 1 0 0 Common Stock 2026-02-24 4 S 0 400 560.3004 D 651549 D Common Stock 2026-02-24 4 S 0 412 561.4402 D 651137 D Common Stock 2026-02-24 4 S 0 223 562.245 D 650914 D Common Stock 2026-02-24 4 S 0 124 563.651 D 650790 D Common Stock 2026-02-25 4 S 0 318 560.3742 D 650472 D Common Stock 1623328 I Held in TWP Holdings Common Stock 4000 I Kimberly R. Powell The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $560.00 to $560.980, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $561.00 to $561.980, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $562.00 to $562.520, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $563.275 to $564.080, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $560.00 to $560.50, inclusive. These shares are held directly by the spouse of Thomas W. Powell. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, the reporting person disclaims beneficial ownership of any such securities, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that such reporting person is the beneficial owner of such securities for purposes of Section 16 or otherwise. /s/ Thomas W. Powell 2026-02-26