UPL

Ultra Petroleum Corp

A Houston-based independent oil and gas producer that became one of the largest natural gas extractors in Wyoming. Born in 1979 as a dormant Canadian shell company, it was revived in the early 1990s by a new management team and focused on the tight-sand gas of the Pinedale and Jonah fields in the Green River Basin, pioneering multi-stage hydraulic fracturing to unlock rock that had defied drillers since 1939.