X0306 4 2020-12-09 0 0001403752 Zymeworks Inc. ZYME 0001761857 Klompas Neil A C/O ZYMEWORKS INC. 1385 WEST 8TH AVENUE, SUITE 540 VANCOUVER A1 V6H 3V9 BRITISH COLUMBIA, CANADA 0 1 0 0 Chief Financial Officer Common Shares 2020-12-09 4 M 0 8380 4.1945 A 17502 D Common Shares 2020-12-09 4 M 0 16620 5.6708 A 34122 D Common Shares 2020-12-09 4 S 0 25000 53.2453 D 9122 D Common Shares 700 I Held by spouse Stock Option (Right to Buy) 4.1945 2020-12-09 4 M 0 8380 0.00 D 2013-01-01 2022-01-01 Common Shares 8380 0 D Stock Option (Right to Buy) 5.6708 2020-12-09 4 M 0 16620 0.00 D 2014-01-01 2023-01-01 Common Shares 16620 4330 D The exercise price of the stock option is CAD5.37. The U.S. dollar equivalent of the exercise price is $4.1945 using the Bank of Canada exchange rate for December 9, 2020 (CAD1.00 = $0.7811). The exercise price of the stock option is CAD7.26. The U.S. dollar equivalent of the exercise price is $5.6708 using the Bank of Canada exchange rate for December 9, 2020 (CAD1.00 = $0.7811). The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $53.00 to $53.95, inclusive. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on December 9, 2020 at each separate price. Stock options vest as follows: (i) 25% of underlying shares on first anniversary of grant date and (ii) remainder of underlying shares in 36 equal monthly installments on last day of month following the first anniversary of grant date. The grant date was ten years before the listed expiration date. /s/ Daniel Dex, Attorney-in-Fact 2020-12-11