In 1994, two economists, Avinash K. Dixit of Princeton and Robert Pindyck of MIT wrote an influential book called Investment Under Uncertainty that showed that, since so many investment decisions are irreversible, people wait to acquire more information before they jump in.

FORBES: Move up http://i.forbesimg.com t Move down

Before then, Marathon Oil ( MRO) had a 50% stake in Pilot, which made the company ineligible. (For more information about eligibility, click here.) In the summer of 2009, Pilot agreed to acquire Flying J travel plazas.

FORBES: PE Firm Sells Its Share of Pilot Travel Centers