California Code, Government Code - GOV § 20178

(a) The board shall credit all contributions of members in the retirement fund with interest at an interest crediting rate of 6 percent compounded at each June 30. The retired member reserves in the retirement fund shall be credited with the lesser of the current actuarial interest rate or the current annual interest rate compounded at each June 30. The interest amount that would have been credited to the member's account on and after June 30, 1991, had the account been credited with the lesser of the current actuarial interest rate or the current annual interest rate, rather than at the 6-percent interest crediting rate, shall be credited to retired member reserves.

(b) Notwithstanding subdivision (a), the difference between the interest amount that was credited to the account of any state or school member of this system who was paid his or her accumulated contributions on or after June 30, 1991, and the lesser of the current actuarial interest rate or the current annual interest rate, shall be transferred to the state or school account, as appropriate, established by the board under Section 21337 to fund the purchasing power protection allowance for retirees, survivors, or beneficiaries of state or school employers.

(c) Notwithstanding subdivisions (a) and (b), if the current net earnings rate for state or school members exceeds the interest rate used to credit the retired member accounts of state or school employers, in addition to the amounts transferred to the separate accounts established for state and school employers under Section 21337, the remaining amounts shall be credited to employer accounts.

(d) The current annual interest rate may be lower than the current actuarial interest rate.