The unseen hand that moves the world's oil

Vitol built this state-of-the-art storage terminal in Cape Canaveral, Fla. Open since 2010, it supplies the nearby port, the Orlando airport, and gas stations across central Florida.

The man who runs the biggest, most important company you've never heard of bounds into the room with a grin. In his elegant navy suit, and with his cheerfully self-effacing personality, Ian Taylor is the very model of a British executive. The 57-year-old is bald on top and graying on the sides, yet he sparkles with boyish enthusiasm. It almost goes without saying that he's eloquent, having studied politics, philosophy, and economics at Oxford. His firm is just one player in a "whacking great" industry, he explains. But he's happy to discuss his business. Simply put: He buys oil in one place and sells it in another, hoping to make a profit. In reality, it's a bit more complicated than that.

Taylor is CEO of the Vitol Group, the world's largest independent oil trader. According to results provided by the company, Vitol, which is a private partnership, racked up revenues of $303 billion in 2012. That would make Vitol the biggest private company in the world by sales, ahead of commodities industry peers such as Cargill and Koch Industries. If Vitol were publicly traded, its reported revenues would have ranked it No. 7 on last year's Fortune Global 500, ahead of Chevron and Toyota. Margins in the trading business are razor thin, but the company's profits are divvied up among just 350 or so shareholders.