Cost of acquisition rules define purchase price, fair market value options and special bases for financial and pre existing equity assets. Section 90 defines cost of improvement and cost of acquisition for capital gains: improvement is nil for goodwill/intangibles and otherwise capital expenditure on additions by the assessee or previous owner; acquisition is generally the purchase price where acquired by purchase (with deduction for prior depreciation for goodwill), nil in other cases, and subject to specific allocation rules for financial asset entitlements, pre existing equity holdings revaluation options using fair market value, and demutualisation treatment of shares and trading rights.