Former President Donald J. Trump’s stake in his social media company is worth half of what it was before his conviction on charges of falsifying business records to cover up a sex scandal during the 2016 presidential campaign

Mr. Trump’s roughly 65 percent stake in Trump Media & Technology Group, the parent of Truth Social, was worth roughly $6 billion on May 30, the day a New York jury found him guilty on all 34 charges. On Friday, the value of his 115 million shares of Trump Media had dropped to less than $3 billion.

By any measure, Mr. Trump’s stake is still worth a tremendous amount of money. But the social media company’s shares have been extremely volatile, as highlighted by the steep decline this month.

Trump Media’s stock price traded as high as $66 after its merger with a public shell company in late March, and as low as $23 a few weeks later. The stock traded just above $25 on Friday, down 5 percent on the day.

The big swing in price is a potential sign of more volatility to come when a provision that bars Mr. Trump from selling his shares expires in September, a few weeks before the presumptive Republican nominee faces President Biden in a presidential election rematch.

Trump Media’s stock has also been weighed down by securities regulators this week allowing early investors in the company to potentially sell tens of millions of shares. Trump Media warned in a filing that the move by the Securities and Exchange Commission “could result in a significant decline in the public trading price of our common stock.”