Expand Energy Corporation, headquartered in Oklahoma City, is the largest independent natural gas producer in the U.S. based on net daily production. The company operates in the Appalachian Basin of the Marcellus Formation in Pennsylvania and West Virginia, as well as the Haynesville Shale in Northwestern Louisiana.

In 2024, the company produced 3,758 MMcfe of natural gas per day. In 2024, 41% of production was from the Haynesville Shale, 48% of production was from Northeast Appalachia, and 11% of production was from Southwest Appalachia.

As of December 31, 2024, the company had 20,800 Bcf of proved reserves. It also had interests in 8,000 gross productive wells.

The company was founded in 1989 as Chesapeake Energy by Aubrey McClendon and Tom L. Ward with an initial investment of $50,000. McClendon named the company after Chesapeake Bay due to his love of the region. Ward left the company in 2006 to establish SandRidge Energy.

In 1993, the company became a public company via an initial public offering, with a valuation of $25 million.

Focusing on a strategy of drilling horizontal natural gas wells in unconventional reservoirs, the company built a sizable position in the Golden Trend and Sholem Alechem fields of South-central Oklahoma and in the Giddings field of Southeast Texas.

In the mid-1990s, the company unsuccessfully attempted to extend the Austin Chalk play into western and central Louisiana.

In 1997, the company wrote down the value of its assets by over $200 million, approximately equal to shareholder's equity at the time, due to low commodity prices and implemented a turnaround plan.