X0306 4 2021-05-10 0001423221 Quanex Building Products CORP NX 0001251789 GRIFFITHS WILLIAM C 1800 WEST LOOP SOUTH, SUITE 1500 HOUSTON TX 77027 1 1 Executive Chairman Common Stock 2021-05-10 4 S 0 100 29.00 D 233536 D This sale was effected pursuant to a Rule 10b5-1 preset diversification program previously adopted by the reporting person. /s/ Paul B. Cornett, Power of Attorney 2021-05-12