Antero Resources announced that proved reserves at June 30, 2012 were 4.3 Tcfe, a 1% decrease compared to reserves at December 31, 2011, pro forma for the disposition of Antero's Arkoma Basin assets which were sold in the second quarter of 2012. Proved, probable and possible reserves (3P) increased by 20% to 19.6 Tcfe while Antero's 3P liquids reserves increased by 49% to 1.0 billion barrels at June 30, 2012. Antero also announced that as of June 30, 2012 its natural gas hedge position, after excluding hedges associated with the Arkoma Basin assets, increased from year-end 2011 by 47% to 823 Bcfe with an average NYMEX-equivalent price of $5.15 per MMBtu.

Proved Reserves

Despite a 23% decline in Piceance Basin SEC pricing and an 18% decline in Appalachian Basin SEC pricing, proved reserves decreased by only 1% to 4.3 Tcfe as of June 30, 2012. Also at mid-year 2012, 73% of the Company's proved reserves were in the Marcellus Shale and 27% were in the Piceance Basin. Proved reserves by volume were 76% natural gas, 22% NGLs and 2% crude oil. As of June 30, 2012, only 16% of Antero's 252,000 net acres of Marcellus Shale leasehold were classified as proved. Antero's Marcellus Shale proved reserves increased by 12% in the first six months of 2012.

Excluding the Arkoma Basin assets, proved developed reserves increased by 36% from year-end to 817 Bcfe as of June 30, 2012 as a result of the successful execution of Antero's development drilling plan. Proved undeveloped reserves decreased in total by 6%, primarily due to a 28% decrease in Piceance undeveloped reserves driven by 23% lower pricing compared to year-end 2011. The decrease in Piceance Basin proved undeveloped reserves was partially offset by a 5% increase in Marcellus Shale proved undeveloped reserves. The sale of Antero's Arkoma Basin assets in June 2012 reduced proved reserves by 659 Bcfe. Proved undeveloped reserves accounted for 81% of total proved reserves at June 30, 2012 as compared to 86% at December 31, 2011, excluding the Arkoma Basin assets.