• Shares of Trump Media, which trades as DJT on the Nasdaq, fell to a new post-merger low.
• Former President Donald Trump is now expected to be able to start selling his nearly $2 billion stake in the company.
• Trump and other early investors have been barred from selling their shares under a lockup agreement that took effect when the company went public in March.

Shares of Trump Media fell to a new post-merger low Thursday, the day that former President Donald Trump is expected to be able to start selling his nearly $2 billion stake in the owner of social media platform Truth Social.

The company, which trades as DJT on the Nasdaq, closed down nearly 6% at $14.70 per share.

Trump, the Republican presidential nominee, owns nearly 57% of DJT's outstanding shares. That stake at Thursday's closing price was worth nearly $1.7 billion — almost half of Trump's estimated on-paper net worth.

Trump, and other early investors, have been barred from selling their shares under a lockup agreement that took effect when the company went public following a merger with a blank-check firm in late March.

Those restrictions were set to expire as soon as the closing bell Thursday.

Trump Media has acknowledged in regulatory filings that the end of the lockup could spur large sales of the company's stock, and even the market's perception of a sell-off could drive down DJT's stock price.

Trump, the majority shareholder, said Friday that he has no plans to sell his stake. His assurance sent the stock soaring higher, though it has since given up those gains.

Other company insiders, however, might try to cash in as soon as they get a chance to do so.

The company's fortunes are tied up with those of Trump, whose use of Truth Social makes him a main draw to the platform.

After soaring in its public trading debut, Trump Media has suffered a monthslong stock slump that has coincided with Trump's tumultuous presidential campaign against Democratic nominee Kamala Harris.

The decline has shaved billions of dollars off Trump Media's market value, bringing it closer in line with what some analysts say the company is actually worth.

Trump Media's earnings reports show it has lost around $344 million on revenue of less than $2 million in the first half of the year. Its revenue depends entirely on ad sales, but its lone product, Truth Social, generates just a fraction of the user base of more established social media sites.

Yet the company still boasts a market capitalization of nearly $3 billion, as some retail investors appear to be buying into it as a way to support Trump or bet on his political standing.

After Trump narrowly survived an assassination attempt at a campaign rally in July, Trump Media shares skyrocketed. But the stock began to fall later that month, around the time Harris replaced President Joe Biden as the Democratic nominee and quickly narrowed Trump's lead in the polls.

The stock rose again in advance of the Sept. 10 presidential debate, which some saw as a bigger risk for Harris than Trump. But after Trump's performance drew poor reviews — both in the polls and from a number of conservative commentators — DJT shares plummeted to a new post-merger low.

With the lockup expiration looming, Trump Media has sought an injunction that would block ARC Global, a sponsor of the merger that took the company public, from immediately selling its shares.

A judge in Florida said Wednesday that he would not grant an injunction.

A Delaware judge had ruled Monday that Trump Media breached an agreement with ARC and must grant the investor a larger share of its stock.

— CNBC's Josephine Rozzelle contributed reporting.