S.14A : Disallowance of expenditure-Exempt income-Schedule bank-Stock in trade-Investment in shares and securities-Shares and securities are held as stock in trade-No disallowance can be made-Common funds-Non interest bearing funds more than the investment-There is no statutory provision which obligated the assessee to maintain separate accounts which might justify proportionate disallowance-Proportionate disallowance of expenses cannot be made. [R. 8D]