N.Y. Gen. City Law § 20-C
Notwithstanding any other provision of law, each city of the state, acting through its board of estimate or other analogous governing body, may authorize its comptroller or other chief fiscal officer, to set aside in a special fund, all or part of the proceeds of the sale of serial or other city bonds sold prior to February first, nineteen hundred forty-five, which such comptroller or other chief fiscal officer may determine, in his discretion, not to be needed immediately for making payments for the purposes for which such bonds were issued, and may authorize such comptroller or other chief fiscal officer to invest such fund in direct obligations of the United States which may be issued in registered or inscribed form until such time as funds are needed or should be available for the purposes for which such bonds were issued. Such comptroller or other chief fiscal officer may thereupon invest such fund in such obligations and may thereafter sell all or any of such obligations whenever he deems such sale advisable. Nothing in this section contained shall be deemed to refer to refunding bonds.
N.Y. Gen. City Law § 20-C