Section 7(4)(a) in The State Financial Corporations Act, 1951
(a)repayable on demand or on the expiry of a fixed period not exceeding ninety days from the date on which the money is so borrowed against the security of-(i)stocks, funds and securities (other than immovable property) in which a trustee is authorised to invest trust money by any law for the time being in force in India, or(ii)such bills of exchange and promissory notes as are eligible for purchase or re-discount by the Reserve Bank or as are fully guaranteed as to the repayment of the principal and payment of interest by a State Government;