Apportionment of tax credit: account-based credit adjustment or valuation-based reduction when goods change use or are transferred. Apportionment of tax credit reduces claimed input tax credit when goods bought for specified purposes are later used for other purposes or transferred/exported. If commodity-wise accounts clearly correlate use, reduction equals input tax on purchases used for other purposes or follows the transfer-specific reduction mechanism. If such accounts are not maintained, reduction is calculated using the higher of immediate pre-use purchase price or fair market value, with transfer/export adjustments reduced according to the transfer rule.