X0306 4 2022-02-28 0 0001499453 Spirit of Texas Bancshares, Inc. STXB 0001738140 Bass Dean O. 1836 SPIRIT OF TEXAS WAY CONROE TX 77301 1 1 0 0 Chairman & CEO Common Stock 2022-02-28 4 M 0 5000 12 A 262403 D Common Stock 2022-02-28 4 M 0 8076 13 A 270479 D Common Stock 2022-02-28 4 M 0 7692 13 A 278171 D Common Stock 2022-02-28 4 M 0 5187 16 A 283358 D Common Stock 2022-02-28 4 M 0 9000 13 A 292358 D Common Stock 2022-02-28 4 M 0 5333 15 A 297691 D Common Stock 2022-02-28 4 M 0 2619 21 A 300310 D Common Stock 2022-02-28 4 M 0 5000 12 A 305310 D Common Stock 2022-02-28 4 M 0 6924 13 A 312234 D Common Stock 2022-02-28 4 M 0 17308 13 A 329542 D Common Stock 2022-02-28 4 M 0 9813 16 A 339355 D Common Stock 2022-02-28 4 M 0 16000 13 A 355355 D Common Stock 2022-02-28 4 M 0 9667 15 A 365022 D Common Stock 2022-02-28 4 M 0 3000 21 A 368022 D Common Stock 2022-02-28 4 M 0 9381 21 A 377403 D Common Stock 2022-02-28 4 S 0 5000 28.0495 D 372403 D Common Stock 2022-02-28 4 S 0 6924 28.6881 D 365479 D Common Stock 2022-02-28 4 S 0 17308 28.1721 D 348171 D Common Stock 2022-02-28 4 S 0 9813 28.6635 D 338358 D Common Stock 2022-02-28 4 S 0 16000 28.1914 D 322358 D Common Stock 2022-02-28 4 S 0 9667 28.6497 D 312691 D Common Stock 2022-02-28 4 S 0 3000 28.766 D 309691 D Common Stock 2022-02-28 4 S 0 9381 28.6674 D 300310 D Employee Stock Options (right to buy) 12 2022-02-28 4 M 0 5000 0 D 2017-06-01 2022-06-01 Common Stock 5000 0 D Employee Stock Options (right to buy) 13 2022-02-28 4 M 0 8076 0 D 2018-03-21 2023-03-21 Common Stock 8076 0 D Employee Stock Options (right to buy) 13 2022-02-28 4 M 0 7692 0 D 2019-02-20 2024-02-20 Common Stock 7692 0 D Employee Stock Options (right to buy) 16 2022-02-28 4 M 0 5187 0 D 2020-02-19 2025-02-19 Common Stock 5187 0 D Common Stock 13 2022-02-28 4 M 0 9000 0 D 2021-05-26 2026-05-26 Common Stock 9000 0 D Employee Stock Options (right to buy) 15 2022-02-28 4 M 0 5333 0 D 2022-02-23 2027-02-23 Common Stock 5333 0 D Employee Stock Options (right to buy) 21 2022-02-28 4 M 0 2619 0 D 2022-02-25 2028-05-03 Common Stock 2619 0 D Stock Options (right to buy) 12 2022-02-28 4 M 0 5000 0 D 2017-06-01 2022-06-01 Common Stock 5000 0 D Stock Options (right to buy) 13 2022-02-28 4 M 0 6924 0 D 2018-03-21 2023-03-21 Common Stock 6924 0 D Stock Options (right to buy) 13 2022-02-28 4 M 0 17308 0 D 2019-02-20 2024-02-20 Common Stock 17308 0 D Stock Options (right to buy) 16 2022-02-28 4 M 0 9813 0 D 2020-02-19 2025-02-19 Common Stock 9813 0 D Stock Options (right to buy) 13 2022-02-28 4 M 0 16000 0 D 2021-05-26 2026-05-26 Common Stock 16000 0 D Stock Options (right to buy) 15 2022-02-28 4 M 0 9667 0 D 2022-02-23 2027-02-23 Common Stock 9667 0 D Stock Options (right to buy) 21 2022-02-28 4 M 0 3000 0 D 2022-02-25 2028-05-03 Common Stock 3000 0 D Stock Options (right to buy) 21 2022-02-28 4 M 0 9381 0 D 2022-02-25 2028-05-03 Common Stock 9381 0 D Includes 11,863 restricted stock units ("RSUs"), which will vest in five equal annual installments beginning on 02/10/2023, includes 15,000 RSUs, which will vest in five equal annual installments beginning on 04/01/2022, 12,500 RSUs, which began vesting in five equal annual installments on 04/01/2021, and 8,000 RSUs, which began vesting in five equal annual installments on 07/01/2020. /s/ By Michael L. Durham as Attorney-in-Fact for Dean O. Bass 2022-03-02