Some of Twitter’s biggest investors are hanging on to their stock, even as restrictions on selling the shares are set to lift today.

About 480 million shares from Twitter insiders will become eligible for sale tomorrow for the first time since the San Francisco-based company's initial public offering in November. That's more than four times the current amount available for trading, which could push the stock price down if those shareholders sell.

Yet some of Twitter's biggest stock owners who, in total, have at least 205 million shares – including venture capital firm Benchmark and co-founder Evan Williams – have declared they're not letting go of their equity.

That’s a vote of confidence in Twitter, which is grappling with a 39 per cent plunge in its stock this year as investors question the company’s slowing user growth.

"We're going to hold," said Chris Sacca, an early Twitter investor, who manages about 15 per cent of the company's shares through various arrangements. Analysts and other investors are focusing too much on user growth and instead should "just recognize how much money Twitter is going to continue to put up on the board".

Co-founder Jack Dorsey and chief executive Dick Costolo will also keep their stakes, the company said in an April 14th regulatory filing.

Rizvi Traverse Management, whose 14 per cent ownership makes it the single-biggest investor, won’t sell either, people with knowledge of the situation have said. Some of Sacca’s holdings are included in Rizvi. – Bloomberg