Iran Has Huge Hoard of Floating Oil to Clear When Sanctions Lift

Here’s something to watch out for when and if U.S. sanctions on Iran are lifted: a tens-of-millions-of-barrels stash of oil floating on tankers, just waiting to go to buyers.

The Persian Gulf country may be holding as much as 69 million barrels at sea, according to estimates from E.A. Gibson Shipbrokers Ltd., a London-based broker that traces is history back to the 19th century. It is hard to be sure exactly how big the floating stockpile really is because it’s unclear exactly how many ships are being used and how full they are, said Richard Matthews, the firm’s head of research.