X0306 4 2021-07-15 0 0001403752 Zymeworks Inc. ZYME 0001761853 Tehrani Ali C/O ZYMEWORKS INC. 1385 WEST 8TH AVENUE, SUITE 540 VANCOUVER A1 V6H 3V9 BRITISH COLUMBIA, CANADA 1 1 0 0 Chief Executive Officer Common Shares 2021-07-15 4 M 0 3800 4.2713 A 264125 D Common Shares 2021-07-15 4 S 0 3800 36.00 D 260325 D Common Shares 2021-07-16 4 M 0 41191 4.2643 A 301516 D Common Shares 2021-07-16 4 S 0 41191 36.00 D 260325 D Common Shares 55511 I Held by spouse Stock Option (Right to Buy) 4.2713 2021-07-15 4 M 0 3800 0.00 D 2013-01-01 2022-01-01 Common Shares 3800 41191 D Stock Option (Right to Buy) 4.2643 2021-07-16 4 M 0 41191 0.00 D 2013-01-01 2022-01-01 Common Shares 41191 0 D Pursuant to a 10b5-1 plan entered into May 13, 2021. The exercise price of the stock option is CAD5.37. The U.S. dollar equivalent of the exercise price is $4.2713 using the Bank of Canada exchange rate for July 15, 2021 (CAD1.00 = $0.7954). All shares were sold at $36.00 per share. The exercise price of the stock option is CAD5.37. The U.S. dollar equivalent of the exercise price is $4.2643 using the Bank of Canada exchange rate for July 16, 2021 (CAD1.00 = $0.7941). Stock options vest as follows: (i) 25% of underlying shares on first anniversary of grant date of January 1, 2012 and (ii) remainder of underlying shares in 36 equal monthly installments on the last day of month following first anniversary of grant date. /s/ Daniel Dex, Attorney-in-Fact 2021-07-16