California Code, Government Code - GOV § 20309.5

(a) Any person who is a member of the Defined Benefit Program of the State Teachers' Retirement Plan and who subsequently became employed, on or after July 1, 1991, and who continues to be employed by the state to perform service that requires membership in the Public Employees' Retirement System under Section 21071 and who meets the requirements of subdivision (b) of Section 22508.6 of the Education Code may elect to have his or her state service subject to coverage by the Defined Benefit Program of the State Teachers' Retirement Plan and excluded from coverage by the Public Employees' Retirement System.

(b) Upon an election being made pursuant to subdivision (a), the Public Employees' Retirement System shall transfer to the Teachers' Retirement Fund an amount equal to the actuarial accrued liability of the system for the service rendered by the person making the election on or after July 1, 1991, to the date of the election, inclusive.  The actuarial accrued liability shall be calculated based on the actuarial assumptions of the system for the most recently completed actuarial valuation as of the date of the election.