Southeastern Asset Management Inc ., the owner of one of every 10 shares in Chesapeake Energy Corp . (NYSE: CHK), is more bullish on the natural gas producer as CEO Doug Lawler trims costs.

The outlook for Oklahoma City-based Chesapeake has improved because Lawler “has made substantial progress since taking the helm” in June, Southeastern said in a letter to its shareholders April 17.

Lawler’s “capital discipline and operational effectiveness will reward shareholders,” the Memphis-based asset management firm led by O. Mason Hawkins said in the letter. Southeastern is the largest shareholder in Chesapeake, according to data compiled by Bloomberg.

Hawkins teamed with the company’s second-largest shareholder, billionaire activist investor Carl Icahn , last year to remove Chesapeake co-founder and shale gas pioneer Aubrey McClendon . Lawler, a former Anadarko Petroleum Corp . (NYSE: APC) executive, plans to cut spending 20% this year, bringing it down to less than half of 2012 levels as the company sells assets and spins off its oilfield services division.

Chesapeake gained 1.3% to $27.84 April 17 in New York. Since the 47-year-old Lawler’s appointment was announced, the stock has advanced 34%, outperforming the 12% rise in the Standard & Poor’s 500 Index and the 8.3% increase for Exxon Mobil Corp . (NYSE: XOM), the only company that produces more gas in the U.S. than Chesapeake.