X0306 5 2021-12-31 0 0 0 0001667161 Randolph Bancorp, Inc. RNDB 0001429021 Parent William M C/O RANDOLPH BANCORP, INC. 2 BATTERYMARCH PARK, SUITE 301 QUINCY MA 02169 1 1 0 0 President and CEO Common Stock 2020-05-20 5 L 0 L 26 9.25 A 30964 I By IRA Common Stock 24035 D Stock Option (Right to Buy) 8.78 2030-03-31 Common Stock 29412 29412 D Stock Option (Right to Buy) 11.48 2030-08-12 Common Stock 65000 65000 D Includes a deferred reported transaction of 26 shares. Includes 8,000 shares of restricted stock which vest in annual installments of 2,000 shares from April 1, 2022, 10,000 shares of restricted stock which vest in annual installments of 2,500 shares from August 13, 2022 and 1,875 shares of restricted stock which vest in annual installments of 625 shares from August 13, 2022. The options vest in five equal annual installments beginning on April 1, 2021. The options vest in five equal annual installments beginning on August 13, 2021. /s/ William M. Parent 2022-01-28