Twitter said in a filing on Friday (May 27) it will not accept Egon Durban's resignation from the board, two days after shareholders blocked his re-election at an annual meeting.
Durban is an ally of Elon Musk, who has offered to take Twitter private in a US$44 billion deal.
Twitter said Durban failed to receive the support of a majority of the votes in the re-election held earlier this week due to "voting policies of certain institutional investors regarding board service limitations".
Durban, who serves on the boards of six other companies, has agreed to reduce his board service commitments to no more than five public company boards by May 25, 2023, Twitter said.
The social media company added that Durban was an "effective member" of the board and brings "an unparalleled operational knowledge of the industry".
The vote on Wednesday against the re-election could indicate skepticism among shareholders of Musk's plan or his willingness to pay what he offered, but investors are expected to overwhelmingly approve the deal at another meeting yet to be scheduled.
Silver Lake Partners, where Durban is co-CEO, helped put together Musk's US$44 billion acquisition of Twitter. In 2018, Silver Lake offered to help finance Musk's contemplated US$72 billion bid to take electric-car maker Tesla Inc private.
Musk tweeted on May 13 that the Twitter deal was "temporarily on hold" while he sought more information about the proportion of fake accounts on Twitter.
Separately, the US Securities and Exchange Commission said on Friday it was looking into Musk's disclosure of his Twitter stake in April.
Shares of Tesla, where Musk serves as the chief executive officer, were up nearly 5 per cent, while Twitter rose marginally in early trading.