With prices at the pump falling as consumers cut back on transportation costs, crude oil holders are attempting to build up their reserves until prices rise later in the year. So where do companies like Morgan Stanley, Citigroup, and Shell store their supply of crude? In supertankers idling around the world's oceans. The top owner of supertankers, Frontline Ltd., estimates 80 million barrels of crude are now in such tankers-the most in two decades, Bloomberg reported. Pirate dangers aside, using a supertanker for storage costs about $75,000 each day.