X0306 4 2022-01-31 0 0001667161 Randolph Bancorp, Inc. RNDB 0001675925 Kirwin Ryan J. C/O RANDOLPH BANCORP, INC. 2 BATTERYMARCH PARK, SUITE 301 QUINCY MA 02169 0 1 0 0 EVP/Residential Lending Common Stock 2022-01-31 4 M 0 1947 11.48 A 23606 D Common Stock 100 D Common Stock 1352 I ESOP Stock Options (right to buy) 14.66 2027-10-11 Common Stock 16252 16252 D Stock Options (right to buy) 15.00 2029-02-13 Common Stock 10000 10000 D Stock Options (right to buy) 11.48 2022-01-31 4 M 0 1947 0.00 A 2030-08-12 Common Stock 1947 13053 D Includes 2,167 shares of restricted stock which vest on October 12, 2022, 6,000 shares of restricted stock which vest in annual installments of 2,000 shares from February 14, 2022, 800 shares of restricted stock which vest in annual installments of 200 shares from August 13, 2022 and 2,000 shares of restricted stock which vest in one-third annual installments from August 13, 2022. Owned jointly with spouse. The options vest in five equal annual installments beginning on October 12, 2018. The options vest in five equal annual installments beginning on February 14, 2020. Includes 12,000 options which vest in annual installments of 3,000 shares from August 13, 2022. /s/ Lauren B. Messmore 2022-02-02