allowable credits
(5) Allowable credits. The term allowable credits includes any credit against the estate tax liability allowable by any section of the Code or by reason of any treaty obligation of the United States, provided the estate qualifies for and properly claims the credit by complying with all applicable rules for claiming the credit. For instance, the prorated unified credit under section 2102(b)(3) is an allowable credit for qualifying estates if the estate files all necessary forms or statements required by the IRS to claim that credit. (6) United States dollars. The term United States dollars means the official currency of the United States. The term United States dollars includes physical bills and coins for which the value of each bill or coin is equivalent to the face amount of that bill or coin. This definition does not include other physical United States bills or coins with numismatic value because these bills and coins typically do not have a value equal to their face value.