Mich. Comp. Laws § 38.1333
The reserve for member investment plan is the account into which are remitted member contributions as provided in section 43a. The retirement board shall provide for the maintenance of an individual subaccount for each member showing the amount of the member's contributions together with compound interest accumulation on that amount. Member investment plan accumulated contributions refunded to a member upon a member's withdrawal from service or paid to the member's legal representative, estate, or refund beneficiary in the event of the member's or former member's death shall be paid from the reserve for member investment plan. Member investment plan accumulated contributions not refunded to a member or paid to the member's or former member's legal representative, estate, or refund beneficiary shall be transferred from the reserve for member investment plan to the reserve for employer contributions. The member investment plan accumulated contributions of a member, upon retirement or upon death if a retirement allowance is payable, shall be transferred from the reserve for member investment plan to the reserve for retired benefit payments.
MCL 38.1333