Minutes before Trump's announcement, $800 million in trades made on oil prices

At 9.50pm AEDT yesterday, there was a sudden spike in trading on the oil and S&P 500 futures market.

6.50am New York time is an unusual time for a rush on trades on West Texas Intermediate May futures.

But it showed that all of a sudden, a substantial sum of money was bet on oil prices dropping and the stock market rising.

READ MORE: Single Trump post sends oil prices tumbling

Donald Trump has said he is negotiating with Iran, something Iran has denied. (AP)

In the space of a minute, more than $800 million in trades was made on oil futures.

"I am pleased to report that the United States of America, and the country of Iran, have had, over the last two days, very good and productive conversations regarding a complete and total resolution of our hostilities in the Middle East," Trump wrote.

"Based on the tenor and tone of these in depth, detailed, and constructive conversations, witch (sic) will continue throughout the week, I have instructed the Department of War to postpone any and all military strikes against Iranian power plants and energy infrastructure for a five day period, subject to the success of the ongoing meetings and discussions."

The S&P 500 futures market surged and crude oil prices dropped through the floor.

And whoever made those trades made an incredible amount of money.

A White House spokesperson brushed off the suspicious activity.

Oil prices dropped after Trump's announcement. (AP)

"The White House does not tolerate any administration official illegally profiteering off of insider knowledge, and any implication that officials are engaged in such activity without evidence is baseless and irresponsible reporting," Kush Desai told FT.

Hours later, top Iranian politician Mohammad-Bagher Ghalibaf denied the president's claim.

"No negotiations have been held with the US, and fake news is used to manipulate the financial and oil markets and escape the quagmire in which the US and Israel are trapped," he said.

"Iranian people demand complete and remorseful punishment of the aggressors.

"All Iranian officials stand firmly behind their supreme leader and people until this goal is achieved."

Millions of bets were placed on the demise of Iran's late Supreme Leader. (AP)

Today's future market trades are not the first time eyebrows have been raised at suspicious bets before a Trump decision.

Betting app Kalshi has refused to pay out $77 million in winnings to punters who bet Ayatollah Ali Khamenei would be out of office by March 1.

Khamenei was killed by a US and Israeli bombing strike hours before the deadline was reached.

Meanwhile on Polymarket, 150 accounts bet more than a million dollars that the US would strike Iran the next day.

And in January, a Polymarket user made about $570,000 betting that Venezuelan President Nicolas Maduro would be out of office before the end of the month.

They had doubled down on their bet hours before the US seized the leader in a military strike .

Captured Venezuelan President Nicolas Maduro. (Eduardo Munoz/Reuters via CNN Newsource)