Undisclosed income computation for block assessments: aggregate determination, exclusions for prior assessments and transfer pricing, and specified tax treatment. Undisclosed income for a block period comprises disclosed returns plus undisclosed income determined by the Assessing Officer, excluding incomes already assessed or returned prior to search/requisition and entries based on books maintained before search; computation is based on evidence from search, survey or requisition and other material available to the Assessing Officer, with specified exclusions for international and specified domestic transactions and special rules for firms, loss carryforwards, and application of transfer pricing provisions.