The US president's sudden change of heart on targeting Iranian energy sites has raised suspicions of insider trading after thousands of oil contracts were traded in anticipation of a drop in crude prices.

Before financial markets opened in the United States on March 25, the US president stepped back from a threat to target Iranian energy sites. But 15 minutes before Trump's statement, thousands of oil contracts were traded - meaning anyone who placed bet on crude prices dropping would have made a lot of money. It's raising questions on if anyone acted on insider knowledge.