9. Chesapeake Energy ( CHK), the second-largest producer of natural gas in the U.S., is focused on discovering and developing conventional and unconventional natural gas and oil fields onshore in the United States. Chesapeake has major stakes in the Barnett, Fayetteville, Haynesville, Marcellus and Bossier natural gas shale wells and other unconventional liquid plays. Net income for fourth quarter of 2010 was $180 million, compared to a net loss of $530 million in the year-ago quarter. Revenue reported for 2010 fourth quarter was $1.98 billion versus $2.22 million in 2009 fourth quarter. Since 2000, Chesapeake has built the largest combined inventories of onshore leasehold (13.3 million net acres) by the end of 2010 fourth quarter. Of the total acreage, Marcellus Shale accounts for 13%, or 1.73 million net acres. Net production from Marcellus Shale reserves is 215 million cubic feet equivalent (MMCFE) a day with an operating rig count of 32. Analysts polled by Bloomberg give the stock 49% buy ratings. In the last one year, the stock has appreciated 42% and is currently trading at 10.6 times its estimated 2011 earnings.