A financial expert believes that the Trump family members may be guilty of insider trading by using their advance knowledge of Donald Trump’s market-moving tweets to manipulate the stock market.

Howard Fineman, an analyst with NBC News, claimed this weekend that Trump’s family members are likely using their knowledge of tweets that rock the stock market to make money from the volatility.

“My twitter feed is asking a legitimate question: are @realDonaldTrump’s businesses and family profiting from insider knowledge of his pending — market-moving — tweets, comments and bargaining stands?” Fineman wrote on Twitter. “My guess would be yes. The real questions are: who is doing it for him and how?”

Donald Trump’s Twitter feed has been known to move the stock market, especially through his threats of tariffs, attacks on individual companies, and endorsements of others. Bloomberg News has even created a page keeping track of all the times that Trump has tweeted about the U.S. economy, noting that his statements have been known to have wide-ranging effects. The page tracks how the market responds to Trump’s tweets, showing that there often appears to be a direct correlation.

Some experts believe that advance knowledge of when Trump plans to issue these threats or endorsements could allow someone to buy or sell stock accordingly, reaping a profit from the volatility he creates.

Others have already taken notice and started to play the stock market based on some of Donald Trump’s tweets. As the stock market news site Market Realist noted, Trump’s recent threats of higher tariffs on China led at least one major investor to sell off stock investments. The report noted that billionaire Stanley Druckenmiller moved his investments into treasuries instead.

As Druckenmiller later explained to Bloomberg News, Trump’s threats against China made it a difficult climate for investing. So Druckenmiller said he decided to get out of it entirely and into something safer — and far away from Trump’s social media influence.

“When the Trump tweet went out, I went from 93% invested to net flat, and bought a bunch of Treasuries,” the billionaire investor said. “Not because I’m trying to make money, I just I don’t want to play in this environment.”

NBC analyst accuses Trump family of ‘insider’ trading with early knowledge of Trump’s market-moving tweetshttps://t.co/RjmKQN98dR pic.twitter.com/p20ajSAlC0 — Raw Story (@RawStory) June 9, 2019

Though others have previously raised the idea that Donald Trump and his family are personally profiting from the market fluctuations after his tweets, neither they, nor Howard Fineman have offered any direct evidence that would implicate any of the family members.