An errant post on X may have just shaken the stock market, showing how influential — and unreliable — the social media platform can be.

Unsourced “headlines” about a potential “90-day pause in tariffs” sent markets into a state of turbulence Monday morning as investors sought any indication of a reprieve from the Trump administration’s new levies. The problem: It wasn’t true. The White House swiftly denied the rumor shortly after it began to circulate online.

The false posts may have originated from a real Fox News interview with National Economic Council Director Kevin Hassett at around 8:30 a.m. ET. Hassett was asked whether President Donald Trump would “consider a 90-day pause in tariffs,” and he replied in part: “The president is (going to) decide what the president is (going to) decide.”

According to CNN’s analysis, the first X post to claim Hassett said Trump would consider a 90-day pause in tariffs came at 10:11 a.m. ET from an account called “Hammer Capital” with the handle “yourfavorito,” which has barely 1,000 followers.

At about 10:12 a.m., CNN’s Vanessa Yurkevich, who was on the floor of the New York Stock Exchange, said that cheers had broken out, as stock indices — which were already recovering from early-morning lows — suddenly surged.

“Walter Bloomberg,” an account with a much larger following that uses the handle “DeItaone” copy-and-pasted the original rumor along with a siren emoji at 10:13 a.m.

On CNBC, anchors were seemingly baffled, wondering what was causing the turnaround.

CNBC anchor David Faber and his network colleagues wondered aloud about the triggering “headline,” searching their computer screens for a wire service alert or any other indication of what could have caused stock market movements.

By 10:15 a.m., CNBC anchors were reading the news on air.

“I think we can go with this headline, apparently Hassett’s been saying Trump will consider a 90-day pause in tariffs for all countries except for China,” anchor Carl Quintanilla said.

“We’re trying to source that exactly in terms of where that’s coming from,” Faber quickly added. CNBC showed the “headline” on screen less than a minute later.

“HASSETT: TRUMP IS CONSIDERING A 90-DAY PAUSE IN TARIFFS FOR ALL COUNTRIES EXPECT CHINA,” the CNBC banner read, as if the news was confirmed.

By 10:19, Reuters alerted the supposed comments, citing CNBC.

Stocks would later decline as the White House firmly denied the supposed headline. CNBC reporters quickly reported the White House denial, and Reuters updated its stories, later issuing an advisory at 12:28 p.m. withdrawing the original alert along with a statement that the newswire service “regrets its error.”