Stamp duty value cap on historic fair market value limits valuation of land or building for capital gains computation. A proviso to section 55(2)(b) provides that for capital assets that are land or building, the fair market value on the historic valuation date shall not exceed the stamp duty value of the asset, where available. 'Stamp duty value' is defined as the value adopted, assessed or assessable by a Central or State Government authority for payment of stamp duty on the immovable property.