Actual cost adjustments govern asset valuation for business income, including transfers, subsidies, depreciation and corporate restructuring. Section 43 defines actual cost as the assessee's asset cost reduced by amounts met by others, subject to statutory exclusions and reductions for prior research deductions, subsidies, excise duty credits, interest attributable to post-use periods, and anti-avoidance adjustments where transfers inflate cost. Transfers on amalgamation, demerger, corporatisation or between related companies may carry over the transferor's cost or written down value when conditions are met. Written down value is actual cost less depreciation actually allowed, with specified aggregation and adjustment rules for blocks of assets and corporate reorganisations.