X0306 4/A 2020-12-09 2020-12-11 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 17492 D Common Shares 2020-12-09 4 M 0 16620 5.6708 A 34112 D Common Shares 2020-12-09 4 S 0 25000 53.2453 D 9112 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. The Form 4 originally filed is being amended to correct the inadvertent overstatement of the "Amount of Securities Beneficially Owned Following Reported Transactions" by ten (10) shares in each of the first three rows of Table I, column 5. /s/ Daniel Dex, Attorney-in-Fact 2021-01-11