How a false post on X about tariffs swung the stock market

Multi-trillion-dollar stock market swings on Monday appear to have been set off by false reports on Elon Musk’s X. Experts say the episode highlights the social media site’s enduring relevance, even as it helps amplify falsehoods.

How did it happen?

On X, that morphed into a bogus headline that Trump was considering a 90-day pause on tariffs for all countries except China.

From there, the erroneous headline took on a life of its own.

Dozens of other accounts with blue verification badges reshared it. Not long after, news organizations including Reuters and CNBC reported it.

About a minute later, it was posted by the X account “Walter Bloomberg,” which has more than 850,000 followers. Although the account is not affiliated with Bloomberg News, it often shares the news organization’s headlines. The account’s boosting of the false headline prompted chatter among CNBC analysts on live television about a possible 90-day reprieve from Trump’s tariffs.

Reuters, citing CNBC, then published a headline carrying the inaccurate tariff pause report.

Reporters went back-and-forth with the relatively obscure finance-focused X account “Hammer Capital” that appears to have started the rumor. Whoever is behind the account claimed to be merely sharing information from “trading desks,” but would not elaborate.

Attempts to reach the person behind the Hammer Capital account were unsuccessful.

To scholars of disinformation like Kate Starbird at the University of Washington, the market mayhem spurred by posts on X underscores the dangers of social media with both few guardrails and policies in place that incentivize virality over truthfulness.