Valuation for notional interest on security deposits may be added to assessable value when a pecuniary advantage is shown. Notional interest on security deposits or advances is includible in assessable value only if there is evidence that the deposit conferred a direct or indirect pecuniary advantage to the manufacturer; where identical prices are charged or interest is credited to the buyer, notional interest should not be added. The assessing officer, with Chief Commissioner approval, must use valuation procedures and cost-accounting/banking principles to quantify any benefit, and an earlier contrary circular is withdrawn.