53 Pa. Stat. § 15909
The bond ordinance shall provide for the establishment and maintenance of a sinking fund or shall designate a previously established sinking fund for the payment of the interest on the bonds as the same shall become due and payable and the principal of the bonds at stated maturity or upon mandatory or optional redemption and for the payment of State taxes, if any, assumed by the city to be paid on the bonds. Such sinking fund may be an aggregate fund for some or all issues or series of bonds, in which case each issue or series shall participate proportionately therein, or a separate sinking fund may be established for any particular issues or series. Payments into the sinking fund in respect of bonds issued for construction or acquisition of a project shall commence not later than one year subsequent to the completion or acquisition of such project as estimated by the head of the department or agency of the city having jurisdiction and in all other cases payments into the sinking fund shall commence not later than one year subsequent to the date of the bonds. Such payments shall be made in annual or more frequent installments and shall be sufficient in amount to pay, or accumulate for payment, all interest on and principal of the bonds for which such fund is established and all State taxes, if any, assumed by the city to be paid on such bonds, as and when the same shall become due and payable and disbursements shall be made therefrom and applied to the payment of such principal, interest and taxes, if any, at the times and in the amounts all as shall be set forth in the bond ordinance.
Each such sinking fund and any other funds or accounts established by the bond ordinance shall be managed by the chief fiscal officer in accordance with the covenants of the city contained in the bond ordinance and, unless stricter requirements are imposed by the bond ordinance, the moneys therein to the extent not currently required shall be invested from time to time in such securities as may at the time of investment be authorized by law for investment of moneys of the Commonwealth or any of its departments, agencies or instrumentalities or shall be deposited in interest-bearing deposits with any bank, bank and trust company or trust company or in shares of building and loan associations of Federal savings and loan associations. All deposits, including interest-bearing deposits, of moneys in the sinking or other funds, to the extent that the same are not insured by the Federal Deposit Insurance Corporation or the Federal Savings and Loan Insurance Corporation or other federally authorized corporation or agency, shall be secured either as required by the act of April 29, 1929 (P.L. 865), entitled "An act requiring depositories of city funds in cities of the first class to give bond," or as authorized by law for the securing of public moneys, or in accordance with such stricter requirements as the bond ordinance shall provide. Each bank, bank and trust company, trust company, and building and loan association is hereby authorized to so secure such deposits. All moneys deposited in the sinking fund are hereby subjected to a perfected security interest for the bonds for which the fund is established until properly disbursed.
Interest and profits received from investments and deposits of moneys in the sinking fund and other funds shall be added to such fund and may be applied in reduction of or to complete required deposits. Excess moneys in the sinking fund, including moneys for the payment of the interest, principal or premium of bonds unclaimed after the due date for two years, and excess moneys in other funds shall be repaid to the city for its general purposes or applied as may be provided in the bond ordinance, but such repayment of unclaimed moneys shall not discharge such claim which shall continue subject to applicable law.
53 P.S. § 15909