Fair market value rules for charitable and similar entities govern asset and liability valuation, prescribing formulae and valuer qualifications. Rule 17CB prescribes that total liability equals book value on the specified date excluding capital/corpus, reserves, contingent liabilities, non-ascertained provisions and certain tax provisions. Aggregate fair market value of assets equals the sum of fair market values reduced by tax paid (net of refunds) and non-asset items. Quoted shares use average traded prices; unquoted equity shares follow a specified formula combining adjusted book assets, market values of specified items and adjusted liabilities; non-equity securities require a valuation report. Immovable property is the higher of registered valuer open-market value and stamp duty value; business undertakings are valued as net assets; other assets require a registered valuer or specified professional valuer report.