The date on which former President Donald Trump is eligible to offload shares in his social media company is rapidly approaching—though when it finally comes, it’s likely to offer far less of a treasure than it was earlier this year.

Donald J. Trump, the company’s largest shareholder, has said he won’t sell when a lockup agreement expires on Thursday. But other large investors could.

The volatile Trump Media stock will face a crucial day tomorrow. Donald Trump and other insider investors in the Truth Social parent company will be able to sell shares as the lockup period after the March merger with a blank-check firm expires.