According to the magazine, some traders were suspiciously well-positioned ahead of huge swings in the trade war, either by buying or selling hundreds of thousands of electronically traded futures contracts, called "e-minis" on the S&P 500.
The magazine noted that on September 10, a trader or group of traders bought 82,000 e-minis in the last 10 minutes of trading in New York.
Markets surged, and the buyer who bought the e-minis made $190 million, Vanity Fair found.
He emerged an hour after saying that trade war talks were "back on track." That week, the stock market surged, and whoever made that bet had a profit of $1.8 billion, Vanity Fair calculated.
But the following week, Trump lied saying that trade war talks were going well after a phone call with China.
Nevertheless, the S&P bounced 80 points and a person who had bought 386,000 e-minis the week before made $1.5 billion, Vanity Fair found.