-- Investors placed a roughly $950 million bearish oil bet hours before a US-Iran ceasefire, with prices later sliding about 15% to below $100 per barrel, Reuters said in a Wednesday analysis.
At 19:45 GMT Tuesday, traders sold about 8,600 combined lots of Brent and US crude futures, ahead of a key geopolitical announcement, the analysis noted, citing LSEG data.
Later at 22:30 GMT, President Donald Trump announced a two-week ceasefire with Iran, stepping back from earlier threats and triggering a steep drop in crude prices, the analysis said.
Oil futures fell sharply at the start of Wednesday trading, declining around 15% as easing geopolitical tensions reduced supply risk premiums, according to the analysis.
Large directional bets are common in oil markets as traders hedge physical flows, but transactions of this size are typically split to avoid disrupting prices.
Such sizable trades are also rarely executed after settlement at 18.30 GMT, as traders usually rely on algorithmic strategies to gradually place orders across exchanges.
A similar move occurred on Mar. 23, when traders sold about $500 million in oil futures shortly before Trump delayed strikes on Iran's energy infrastructure.
During Tuesday's session, about 6,200 Brent lots and 2,400 West Texas Intermediate futures traded at that time, each representing roughly 1% of total daily volume, according to the analysis.
Trading activity has surged since the conflict began, with average daily Brent volumes rising from around 300,000 lots historically to over 1 million lots in the last four weeks, equivalent to roughly one billion barrels.
has separately reached out to CME Group and the Commodity Futures Trading Commission for any comments.