SEC Form DEFA14A filed by Zymeworks Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

ZYMEWORKS INC.

(Name of Registrant as Specified in its Charter)

N/A

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

OnlineGo to https://www.envisionreports.com/ZYME or scan the QR code login details are located in the shaded bar below.Votes must be received by the closing of polls at the meeting for shares held directly and by 11:59 p.m. ET on December 25, 2025 for shares held via Shareworks.Stockholder Meeting NoticeImportant Notice Regarding the Availability of Proxy Materials for the Zymeworks Inc. Stockholder Meeting to be Held on December 30, 2025Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual stockholders meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The Notice, Proxy Statement and the Annual Report on Form 10-K are available at: https://www.envisionreports.com/ZYMEEasy Online Access View your proxy materials and vote.Step1:Go to https://www.envisionreports.com/ZYME.Step2:Click on the icon on the right to view meeting materials.Step3:Return to the envisionreports.com window and follow the instructions on the screen to log in.Step4:Make your selections as instructed on each screen for your delivery preferences.Step5:Vote your shares.When you go online, you can also help the environment by consenting to receive electronic delivery of future materials.Obtaining a Copy of the Proxy Materials If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before December 20, 2025 to facilitate timely delivery. 2 NOTCOY046UICOnlineGo to https://www.envisionreports.com/ZYME or scan the QR code login details are located in the shaded bar below.Votes must be received by the closing of polls at the meeting for shares held directly and by 11:59 p.m. ET on December 25, 2025 for shares held via Shareworks.Stockholder Meeting NoticeImportant Notice Regarding the Availability of Proxy Materials for the Zymeworks Inc. Stockholder Meeting to be Held on December 30, 2025Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual stockholders meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The Notice, Proxy Statement and the Annual Report on Form 10-K are available at: https://www.envisionreports.com/ZYMEEasy Online Access View your proxy materials and vote.Step1:Go to https://www.envisionreports.com/ZYME.Step2:Click on the icon on the right to view meeting materials.Step3:Return to the envisionreports.com window and follow the instructions on the screen to log in.Step4:Make your selections as instructed on each screen for your delivery preferences.Step5:Vote your shares.When you go online, you can also help the environment by consenting to receive electronic delivery of future materials.Obtaining a Copy of the Proxy Materials If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before December 20, 2025 to facilitate timely delivery. 2 NOT046UIC

Stockholder Meeting Notice Zymeworks Inc.s Annual Meeting of Stockholders will be held on December 30, 2025, at 9:00 a.m. Pacific Time, virtually via the Internet at meetnow.global/MZKC5MK. Proposals to be voted on at the meeting are listed below along with the Board of Directors recommendations. The Board of Directors recommend a vote FOR all the nominees listed and FOR Proposals 2-3:1.Election of Directors:1- Carlos Campoy2- Alessandra Cesano3- Robert E. Landry 2.Advisory vote on the compensation of our named executive officers 3.Ratification of the appointment of KPMG LLP, chartered professional accountants, as auditors for the year ending December 31, 2025 PLEASE NOTE YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please bring this notice with you.Heres how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below.If you request an email copy, you will receive an email with a link to the current meeting materials.PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials."Internet Go to https://www.envisionreports.com/ZYME."Phone Call us free of charge at 1-866-641-4276."Email Send an email to [email protected] with Proxy Materials Zymeworks Inc. in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials.To facilitate timely delivery, requests for a paper copy of proxy materials must be received by December 20, 2025.

C1234567890 XXXMr A Sample Designation (if any) Add1 Add2 add3 add4 add5 add6Notice of Internet Availability of Proxy Materials1234 5678 9012 345Important Notice Regarding the Availability of Proxy Materials for Zymeworks Inc. (the Company)Annual Meeting to be Held on December 30, 2025, at 9:00 a.m. Pacific Time, virtually via the Internet at meetnow.global/MZKC5MK. The U.S. securities regulators have adopted policies that permit the use of notice-and-access for proxy solicitation instead of the traditional physical delivery of proxy materials. The Company is availing itself of the notice-and-access policies and as a result, you will not be receiving a paper copy of the proxy materials in respect of the Annual Meeting unless specifically requested in accordance with the instructions in this Notice.You are receiving this notice to advise that the proxy materials for the above noted meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the meeting are on the reverse side. Your vote is important!THIS IS NOT A FORM FOR VOTINGThis communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The proxy materials, including the Notice and Proxy Statement and Annual Report on Form 10-K are available at:https://www.envisionreports.com/ZYMEEasy Online Access A Convenient Way to View Proxy Materials and VoteWhen you go online to view materials, you can also vote your shares.Obtaining a Copy of the Proxy Materials If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before December 20, 2025 to facilitate timely delivery.ZYMQ024M7BCPUQC01.E.INT/000001/i1234

Shareholder Meeting NoticeThe Companys Annual Meeting of Shareholders will be held on December 30, 2025, at 9:00 a.m. Pacific Time, virtually via the Internet at meetnow.global/MZKC5MK To attend the Annual Meeting and exercise the voting rights directly, you must (1) request a proxy from Computershare Trust Company of Canada at the address below and (2) not have previously submitted voting instructions or have submitted a written revocation of any such previous instructions. VOTING ITEMSThe Board of Directors recommends you vote FOR the following:1.Election of Directors:Nominees01. Carlos Campoy02. Alessandra Cesano03. Robert E. Landry2.Advisory vote on the compensation of our named executive officers3.Ratification of the appointment of KPMG LLP, chartered professional accountants, as auditors for the year ending December 31, 2025We encourage you to access and review all of the important information contained in the proxy materials before voting.PLEASE NOTE YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must either vote online or request a paper or email copy of the proxy materials and a voting instruction card.To assure your representation at the Annual Meeting, please complete, sign, date and return the voting instruction card that is delivered to you.Shareholders who do not wish to attend the Annual Meeting or do not wish to vote in person can vote by voting instruction card. A registered shareholder must return the completed voting instruction card to the Company:(a)by delivering the voting instruction card as instructed therein, which voting instruction card must be received by 2:00 pm Eastern Time, December 24, 2025(b)by internet at www.investorvote.com not later than December 24, 2025 at 2:00 pm Eastern Time or(c)by telephone by calling toll-free in North America at 1-866-732-8683 and following the instructions no later than December 24, 2025 at 2:00 pm Eastern Time.If you are a non-registered shareholder (i.e. you own your shares through an intermediary such as a bank, trust company or broker), you can vote your shares by following the instructions provided by your intermediary.How to Obtain Paper or Email Copies of the Proxy MaterialsShareholders may request to receive paper or email copies of current and future meeting materials by mail or email at no cost. Requests for copies may be made using your Control Number located in the shaded bar on the reverse side of this notice. If you request an email copy, you will receive an email with a hyperlink to the proxy materials. Registered shareholders may enroll to receive future meeting materials by email by visiting www.computershare.com/eDelivery and clicking on eDelivery Signup.To attend the Annual Meeting in person and exercise voting rights directly, please contact Computershare Trust Company of Canada at the following address: 3rd Floor, 510 Burrard Street Vancouver BC, V6C 3B9, or call/email [email protected]/236 982 4155.Request a paper copy of the proxy materials:BY TELEPHONE: Call Toll Free, within North America at 1-866-641-4276. BY INTERNET: Visit www.investorvote.com/ZYMEBY EMAIL: Send a request to [email protected] with Proxy Materials in the subject line.024M8B