X0306 4/A 2021-03-09 2021-03-11 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 2021-03-09 4 S 0 1000 23.58 D 218492 D Common Stock 2021-03-10 4 S 0 1000 24 D 217492 D The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 8, 2021. The original Form 4, filed on March 11, 2021, is being amended by this Form 4 amendment solely to correct an administrative error, which misreported that 1,000 shares of Issuer's common stock were acquired, when in fact 1,000 shares of the Issuer's common stock were disposed of. The original Form 4, filed on March 11, 2021, is being amended by this Form 4 amendment solely to correct an administrative error, which misreported that the sale occurred on March 9, 2011, when in fact the sale occurred on March 10, 2021. The original Form 4, filed on March 11, 2021, is being amended by this Form 4 amendment solely to correct an administrative error, which misreported that 1,000 shares of Issuer's common stock were acquired on March 9, 2021, when in fact 1,000 shares of the Issuer's common stock were disposed of on March 10, 2021. /s/ By Michael L. Durham as Attorney-in-Fact for Dean O. Bass 2021-03-11