Chesapeake Energy Corp.’s original chief financial officer is resigning to run a hydraulic fracturing services company in which the producer holds a 26% stake.

Marcus Rowland, who is resigning after 18 years as CFO on Oct. 29, will be president of Cisco, TX-based Frac Tech Services LLC, which Chesapeake said is one of the largest providers of hydraulic fracturing services in the U.S.

“Marc was Chesapeake’s first CFO and he has seen the highs and the lows along the way and always helped us take advantage of the next opportunity. Among his many achievements during his career at Chesapeake has been his stewardship of the company’s strategic and financially important investment in Frac Tech, which was a much smaller player in the hydraulic fracturing market in 2006 when Chesapeake made its first investment,” said Chesapeake CEO Aubry McClendon.

McClendon said Frac Tech “is likely worth well over $1 billion.” Chesapeake has invested approximately $375 million in Frac Tech. Rowland will help strengthen Frac Tech’s management team as the company prepares for the next phase of its growth, Chesapeake said. Rowland will retain his seat as a director of Chesapeake Midstream Partners LP.

Domenic J. Dell’Osso, Chesapeake vice president of finance and CFO of Chesapeake Midstream Development LP, is to become Chesapeake’s new CFO. Before joining Chesapeake in 2008, Dell’Osso worked at Jefferies & Co. and Banc of America Securities as an energy investment banker.