The Fortune 500 welcomed 21 new companies to the list this year. Some of them, like energy giant Hess, are actually returning to the list. Hess was one of the original members of the Fortune 500, and stayed there for 63 years. When fuel prices headed south a couple of years ago, it fell off. But with prices on the upswing, it’s back and sitting at number four hundred sixty one. Other companies debut on the list as the result of a corporate split or spin-off.