The Internal Revenue Service today confirms the overpayment and underpayment rates in effect for the calendar quarter beginning October 1, 2008, as those announced in Revenue Ruling 2008-47. Revenue Ruling 2008-47, published September 29, 2008, in Internal Revenue Bulletin 2008-39, announced an overpayment rate of 6 percent (5 percent in the case of a corporation) and an underpayment rate of 6 percent for the calendar quarter beginning October 1, 2008. It also announced an overpayment rate of 3.5 percent for the portion of a corporate overpayment exceeding $10,000 and an underpayment rate of 8 percent for large corporate underpayments for the calendar quarter beginning October 1, 2008.

Revenue Ruling 2008-47 determined these rates from an adjusted federal short-term rate of 3 percent that was computed from the federal short-term rate determined during the month of July 2008. The federal short-term rate and other federal rates determined during the month of July 2008 were published in Revenue Ruling 2008-43. Revenue Ruling 2008-43 announced these rates as the rates to take effect beginning August 1, 2008, under section 1274 of the Internal Revenue Code.

An early release of Revenue Ruling 2008-47 correctly announced the underpayment and overpayment rates for the calendar quarter beginning October 1, 2008, based on an adjusted rate of 3 percent but the early release attributed the rates to the adjusted federal short-term rate determined during the month of August 2008. Revenue Ruling 2008-47, as published in the Internal Revenue Bulletin, correctly attributed the rates to the adjusted federal short-term rate determined during the month of July 2008. The official version of Revenue Ruling 2008-47 is the version published in Internal Revenue Bulletin 2008-39, and should be the only version relied upon.