Oklahoma City's SandRidge Energy Inc. announced today it has filed a registration statement with the U.S. Securities and Exchange Commission for an initial public offering of its common shares.

Previously known as Riata Energy, former Chesapeake co-founder Tom Ward became its largest shareholder in May 2006 and later its chairman and CEO. Two months later, the company announced it would move its headquarters to Oklahoma City.

In September 2006, the oil and gas company entered a $1.5 billion agreement to acquire Dallas-based NEG Oil and Gas and changed its name to SandRidge Energy.

Ward is a member of the ownership group that purchased the National Basketball Association's Seattle Supersonics franchise and the Women's National Basketball Association's Seattle Storm franchise. Named along with former Chesapeake Energy colleague Aubrey McClendon to the Forbes list of the top 400 wealthiest Amercians, Ward also invested in local television network, KSBI-TV/DT.

SandRidge focuses its exploration and production activities in West Texas where it has assembled a large, focused acreage position, the Cotton Valley Trend in East Texas and the Gulf Coast. SandRidge also owns oil and gas properties in the Piceance Basin of Colorado, the Gulf of Mexico, and the Anadarko and Arkoma Basins of Oklahoma and Arkansas.

Lehman Brothers Inc., Goldman, Sachs & Co. and Banc of America Securities LLC will act as joint book-running managers and representatives of the underwriters.