npv oF CAsh FloW AFteR InCoMe tAXes usInG GlJ JAnuARY 1, 2011 FoReCAst pRICes AnD Costs  (1) nET ASSET vALUE (“nAv”) hIstoRICAl nAv – DIsCounteD At 10 peR Cent  (1) 25 ARC ResouRCes AnnuAl  report 10 (2) the value of Arc’s reserves increased due to reserve additions and declined due to a decrease in the natural gas price assumptions used  by glJ as at december 31, 2010. (1) Additional information on reserves is available in the Annual information form and in the february 10, 2011 news release titled “Arc  resources ltd. 2010 year-end reserves increase by 29 per cent”. The following net asset value table shows what is normally referred to as a “produce-out” nAv calculation  under which the current value of ARC’s reserves would be produced at forecast future prices and costs and  do not necessarily represent a “going concern” value of ARC. The values presented below are at a point  in time and are based on various assumptions including commodity price forecasts and foreign exchange  rates, which will var y over time. It should not be assumed that the net present values estimated by gLJ  represent the fair market value of the reserves. (1) Additional infor mation on reserves is available in the Annual information form and in the february 10, 2011 news release titled “Arc  resources ltd. 2010 year-end reserves increase by 29 per cent”. npV of cAsH floW After  incoMe tAXes (1)  undiscounted discounted discounted discounted discounted $Millions At 5%  At 10%  At 15%  At 20% Proved Producing  6,375  4,305  3,303  2,715  2,326 Proved Developed non-Producing  336  216  157  123  101 Proved Undeveloped  1,720  985  593  359  210 Total Proved  8,432  5,505  4,053  3,197  2,637 Probable 4,086 1,848 1,042 666 460 Proved plus Probable  12,518  7,353  5,095  3,863  3,097 nAV At deceMBer 31  $Millions, eXcept per sHAre/unit AMounts 2010 2009 2008 2007 2006 value of Proved Plus Probable Reserves discounted at 10% (Before Tax)  $6,350 (2) $5,805 (2) $5,292 $4,651 $4,056 Undeveloped Lands  413 359 428 229 109 Reclamation Fund  25 33 28 26 31 Working Capital Deficit (69) (56) (60) (38) (52) Risk Management Contracts 54 (15) 1 (36) (9) Long-term Debt  (804) (846) (902) (715) (687) Asset Retirement Obligation (29) (27) (57) (26) (62) net asset value  $5,940 $5,253 $4,732 $4,091 $3,386 Shares/Units outstanding (000’s)  284,380 238,984 219,182 213,179 207,173 nAv per share/unit before tax  $20.89 (2) $21.98 (2) $21.59 $19.19 $16.3 4 PROvED PRODUCIng PROvED nOn-PRODUCIng PROBABLE 44% 25% 31% COMPAnY InTEREST RESERvES BY CLASSIFICATIOn 06 07 08 09 10 CUMULATIvE DISTRIBUTIOn PER UnIT (USIng 2006 AS THE BEnCHMARK YEAR) * proved plus probable DISTRIBUTIOn PER UnIT nAv/UnIT AT YEAR-EnD* PER UnIT gROWTH $ 25 20 15 10 5 0