X0306 4 2020-11-10 0 0001532346 Atreca, Inc. BCEL 0001773750 Greenberg Norman Michael C/O ATRECA, INC., 450 EAST JAMIE COURT SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Scientific Officer Class A Common Stock 2020-11-10 4 M 0 4500 4.56 A 4500 D Class A Common Stock 2020-11-10 4 S 0 4500 15.1028 D 0 D Stock Option (right to buy) 4.56 2020-10-19 4 M 0 4500 0.00 D 2026-05-09 Class A Common Stock 4500 16929 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 16, 2020. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.00 to $15.47, inclusive. The reporting person undertakes to provide to Atreca, Inc., any security holder of Atreca, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this Form 4. 1/4 of the Option vested on 5/2/2017 and 1/48 of the Option vests in equal monthly installments as measured from 5/2/2017. The shares subject to this option are early exercisable, subject to the Issuer's right to repurchase. If applicable, vesting accelerates as provided in, and subject to the terms and conditions of, that certain Executive Employment Agreement between the Issuer and the Reporting Person, as may be amended from time to time. /s/ Herbert Cross, attorney-in-fact 2020-11-12