Former President Donald J. Trump’s stake in Trump Media & Technology Group, his social media company, could be worth as much as $4 billion once a long-delayed merger closes.

The deal, with Digital World Acquisition Corp. — a publicly traded shell company — could provide him with a potential financial lifeline at a time when he must come up with the cash to pay a $454 million penalty following a New York judge’s ruling in a civil fraud case.

Digital World has scheduled a March 22 shareholder vote on the merger with Trump Media, whose flagship product, Truth Social, has become the social media platform of choice for Mr. Trump to attack his critics and political opponents.

But even if the deal closes, Mr. Trump would need to get a waiver from a lockup provision that restricts major stockholders from selling shares for at least six months. Trump Media did not respond to a request for comment.

Here’s a look at the challenges the deal has faced, and what could lie ahead for Mr. Trump if it closes.

Why has the merger between Trump Media and Digital World taken so long to close?

The proposed merger between Trump Media and Digital World, a special purpose acquisition company, or SPAC, was announced in October 2021. But the deal was held up by a two-year investigation by the Securities and Exchange Commission into talks between the companies that took place before Digital World went public. SPACs, which sell shares to investors before they can buy a company, aren’t supposed to have a deal lined up before their I.P.O. Digital World raised $300 million in its I.P.O. in September 2021.