SinoMab BioScience Limited — Capital/Financing Update 2023

Nov 6, 2023

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement.

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SinoMab BioScience Limited 中國抗體製藥有限公司

(Incorporated in Hong Kong with limited liability)

(Stock code: 3681)

GRANT OF SHARE OPTIONS

This announcement is made pursuant to Rule 17.06A of the Rules Governing the Listing of Securities on The Stock Exchange of Hong Kong Limited (the ‘‘Listing Rules’’).

The board (the ‘‘Board’’) of directors (the ‘‘Director(s)’’) of SinoMab BioScience Limited (the ‘‘Company’’) hereby announces that on 6 November 2023, 10,062,400 share options (the ‘‘Share Options’’) were granted by the Company (the ‘‘Grant’’) under its share option scheme adopted at the extraordinary general meeting held on 26 October 2022 (the ‘‘2022 Share Option Scheme’’) to an eligible person (the ‘‘Grantee’’), who is a senior management of the Company, to subscribe for an aggregate of 10,062,400 new shares of the Company (the ‘‘Shares’’), subject to acceptance of the Grantee. Details of the Grant are set out below:

Date of Grant 6 November 2023 Categories of Grantee Employee (senior management of the Company) Exercise price of Share HK$1.102 per Share Options granted Number of Share Options 10,062,400 granted Closing price of the Shares on HK$1.100 per Share the date of Grant Average closing price of the HK$1.102 per Share Shares for the five consecutive trading days prior to the date of Grant

Exercisable period of The Share Options are exercisable for a period of 10 Share Options years commencing from 7 November 2024 to 6 November 2034

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Vesting Schedule of 100% vested on 7 November 2024, being the date of 12 Share Options months after the Date of Grant Grantee The Grantee is not a Director, chief executive or substantial shareholder of the Company, nor an associate (as defined under the Rule 14A.06 of the Listing Rules) of any of them. Performance Target No performance target is stipulated in the Grant. The remuneration committee of the Company is of the view that the Grant forms part of the management agreement between the Company and the Grantee for the purpose of attracting and retaining the Grantee. This aligns with the purpose of the 2022 Share Option Scheme. Clawback Mechanism No clawback mechanism is stipulated in the Grant. The remuneration committee of the Company is of the view that clawback mechanism is not necessary as the scheme rules of the 2022 Share Option Scheme already provided the lapse and cancellation of options in different scenarios and provided enough protection to the Company’s interests. Number of Shares available 15,093,620 for future grant under scheme mandate Number of Shares available 10,062,404 for future grant under service provider sublimit (Note)

Note: service provider sublimit is within the scheme mandate.

By Order of the Board SinoMab BioScience Limited Dr. Shui On LEUNG

Executive Director, Chairman and Chief Executive Officer

Hong Kong, 6 November 2023

As at the date of this announcement, the executive Director is Dr. Shui On LEUNG, the nonexecutive Directors are Dr. Haigang CHEN, Mr. Xun DONG, Dr. Wenyi LIU, Mr. Lei SHI and Dr. Jianmin ZHANG, and the independent non-executive Directors are Mr. George William Hunter CAUTHERLEY, Mr. Ping Cho Terence HON, Dr. Chi Ming LEE and Mr. Dylan Carlo TINKER.

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