53 Pa. Stat. § 881.108
The Pennsylvania Municipal Retirement Fund shall consist of the money received from municipalities arising from contributions by municipalities, from payroll deductions from salary or compensation of members, and other contributions made by members through the municipality to the system, from DROP participants and from transfers made from municipal retirement or pension systems and credited as provided in this act, and investment earnings thereon.
The fund shall be a trust and the assets of the system shall be held in trust. No part of the assets of the system shall be used for or diverted to purposes other than for the exclusive benefit of the members, their spouses or the members' beneficiaries prior to the satisfaction of all liabilities of the system with respect to them. The assets of the fund shall only be used to pay:
Contributions made by municipalities toward superannuation retirement and death benefits of members shall be credited to the municipal account of said fund, contributions made by municipalities toward disability retirement of members shall be credited to the total disability reserve account of said fund, retirement benefits paid to DROP participants shall be credited to the subsidiary DROP reserve account and payroll deductions and other contributions of members shall be credited to the member's account of said fund. Transfers made from existing municipal retirement or pension systems shall be credited as provided in this act.
The board shall keep separate accounts of each municipality and for each separate class of employes enrolled by that municipality under the several articles of this act, except the total disability reserve account and the retired member's reserve account which shall be maintained as pooled accounts. Each municipality and the members thereof shall be liable to the board for the amount of contributions required to cover the cost of the retirement allowance and other benefits payable to such members.
Upon the granting of a superannuation or voluntary or involuntary withdrawal retirement allowance to any contributor, the amount of such contributor's accumulated deductions in the member's account shall lose their status as accumulated deductions and shall be transferred to the retired member's reserve account and the actuarial equivalent of the municipal annuity shall be similarly transferred from the municipal account to the retired member's reserve account.
Upon the granting of a superannuation retirement allowance to any DROP participant, the full amount of the DROP participant's monthly retirement benefit shall be deposited monthly to a subsidiary DROP participant account in the subsidiary DROP participant reserve account until the DROP participant terminates employment.
Upon the granting of a disability retirement allowance to any contributor, there shall be transferred to the retired member's reserve account the amount of the contributor's accumulated deductions in the member's account, the amount of the equivalent actuarial value to the municipal annuity, and such additional amount from the total disability reserve account as is needed in addition thereto to provide the actuarial equivalent of the total disability allowance to which the contributor is entitled.
53 P.S. § 881.108