Is Donald Trump’s erratic behavior fueling a business model? Some Wall Street options traders are beginning to suspect so. They’ve taken note, with increasing alarm, of people making strange bets tied to Trump’s actions and then cashing in bigly when the odd bets pay off. “If you had the ability to make hundreds of millions of dollars, or billions, and you knew how to hide it and it was impossible to find, wouldn’t you do it?” a longtime Wall Street options trader asks me sarcastically.

There is an old saw on Wall Street about how if you could somehow get tomorrow’s Wall Street Journal today, you could make a fortune. Advance knowledge of presidential actions might provide a similar advantage, and some unusual trading patterns are fueling gossip and suspicion on the Street.

Take, for example, what happened in the last 30 minutes of trading on Friday, June 28 at the Chicago Mercantile Exchange. By that time Trump was already in Osaka, Japan—which is 14 hours ahead of Chicago—where he would meet for more than an hour with China’s President Xi Jinping. According to the trader, who has decades of experience trading options, while they were meeting on Saturday morning, someone, or a group of people, bought 420,000 so-called “e-minis”—electronically traded futures contracts tied to a wide range of stock indexes—in the last 30 minutes of trading in Chicago on Friday afternoon. The big bet could appear to be that Trump might announce a deal of some sort with Xi about the tariff negotiations, and that on Monday morning, or soon thereafter, the S&P 500 stock index would trade up.

The total volume Friday of the September e-minis was a little more than one million contracts, so a purchase of 420,000 contracts, or about 40% of the day’s volume, in the last few minutes would likely be noticed by astute market watchers. Charts of the e-mini trading that day clearly show a spike up in volume in the last 30 minutes of the day. “What was going on in the world?” the trader asked rhetorically. “At that time? The G20. What if Putin or Xi or MBS knew something positive would be announced on Sunday? Heck, just 10% or 40,000 [e-minis] bought would be $120 million today. Maybe someone got lucky—or listened in to those private meetings.”

On Saturday in Osaka—after the market had closed in Chicago—Trump emerged from his meeting with Xi and announced that the contentious on-again, off-again trade talks with China were back on. “We discussed a lot of things, and we’re right back on track,” Trump said at the news conference following his private meeting with Xi. “Who knew Trump would offer a truce with Xi?” the options trader wondered. “Some lucky trader? Are there any hedge fund traders that might have been tipped off? A simple ‘don’t go short this weekend’ might send a signal to load up on the long side.”

On Monday morning, the market reacted positively to the news that the U.S. and China would resume trade talks, and has kept moving up since, as Trump is always happy to note. On Thursday, June 27—before the G20 meeting began—the S&P 500 index closed at about 2,915. Over a week later, the S&P index is at just below 3,000, an increase of around 84 points, $4,200 per e-mini futures contract. (Each point increase in the index is worth $50 per option.) Whoever bought the 420,000 e-mini options contracts was sitting on about a $1.8 billion profit. “Someone got very, very lucky,” the trader told me.