He owns the majority of its shares, which trade under the ticker DJT, and the stock has been a barometer of the former president’s prospects this election cycle. It soared as polls began tilting his way through most of October.

On Tuesday, shares were so high that Trump Media’s market cap hit $10.8 billion, exceeding Elon Musk’s social media platform X, which has an estimated value of $9.4 billion.

But the next day, DJT shares began selling off, with volatility so extreme that trading was halted several times. By the end of the session, the stock had tumbled 22%, marking the biggest single-day plunge since Trump Media went public in March.

Shares fell 12% on Thursday and 14% on Friday, capping off a 41% dive over just three days. That means the value of Trump’s stake went from $5.9 billion to $3.5 billion during that span, resulting in a $2.4 billion net worth decline, according to CNN.

The turning point may have been Trump’s rally in Madison Square Garden on Oct. 27, when comedian Tony Hinchcliffe called Puerto Rico “a floating island of garbage in the middle of the ocean,” sparking a huge backlash.

The rally, which featured other divisive speakers and remarks, was such a debacle that it may have reversed Kamala Harris’s political fortunes and handed her the White House, according to Thomas Miller, a data scientist at Northwestern University who has built an election model.

Failing to return to the presidency could prove especially costly for Trump and the value of his social media company. If “Trump loses I think it eventually goes to zero,” Mattew Tuttle, CEO of Tuttle Capital Management, told Fortune last month.

But even in that worst-case scenario, Trump will still be a billionaire, albeit a diminished one. Before the selloff, his net worth was somewhere between $7.5 billion and $10 billion, according to estimates from the Wall Street Journal.