Traders work on the floor of the New York Stock Exchange (NYSE) in New York City, USA, March 18, 2026.
Brendan McDermid | Reuters
S&P 500 futures and oil futures saw an unusual burst of activity early Monday, minutes before a market-moving social media post from President Donald Trump.
Around 6:50 a.m., S&P 500 e-mini futures trading on the CME in New York saw a strong and isolated jump in volume, breaking out of an otherwise subdued premarket environment. Given the low liquidity typical of early trading, the sudden breakout was one of the highest volume moments of the session up to that point.
Enlarge symbolArrows point outwards
A similar pattern was observed in the oil markets. Around the same time, West Texas Intermediate May futures also saw a noticeable increase in trading activity, with a significant increase in volume disrupting otherwise calm conditions.
Enlarge symbolArrows point outwards
About 15 minutes later, at 7:05 a.m., Trump said on Truth Social that the U.S. and Iran had been in talks and that he would stop planned attacks on Iranian power plants and energy infrastructure. That announcement sparked an immediate surge in risk assets, with S&P 500 futures rising more than 2.5% before the opening bell. West Texas Intermediate futures fell nearly 6% following the announcement.
Enlarge symbolArrows point outwards
The timing of previous volume spikes in both stocks and crude oil caught traders’ attention, especially given the lack of an obvious catalyst at the time they occurred.
Early morning futures markets tend to be less liquid, which means short bursts of buying and selling can be more noticeable than during regular trading hours. Nevertheless, the trades caused a stir because anyone who bought a large amount of stock futures and sold or shorted crude oil futures at that time made a lot of money just a few minutes later.
The U.S. Securities and Exchange Commission and CME Group did not immediately respond to CNBC’s requests for comment.
Algorithmic and macro-driven strategies can generate rapid flows across asset classes in early trading, even without a single discernible catalyst.
– With assistance from CNBC’s Fred Imbert.
Choose CNBC as your preferred source on Google and never miss a moment from the most trusted name in business news.