Cal. Education Code § 22250

The board and its officers and employees of the system shall discharge their duties with respect to the system and the plan solely in the interest of the members and beneficiaries of the Defined Benefit Program as well as the participants and beneficiaries of the Cash Balance Benefit Program as follows: (a) For the exclusive purpose of the following: (1) Providing benefits to members and beneficiaries of the Defined Benefit Program as well as the participants and beneficiaries of the Cash Balance Benefit Program. (2) Defraying reasonable expenses of administering the plan. (b) With the care, skill, prudence, and diligence under the circumstances then prevailing that a prudent person acting in a like capacity and familiar with those matters would use in the conduct of an enterprise of a like character and with like aims. (c) By diversifying the investments of the plan so as to minimize the risk of large losses, unless under the circumstances it is clearly prudent not to do so. (d) In accordance with the documents and instruments governing the plan and the system insofar as those documents and instruments are consistent with this part and Part 14 (commencing with Section 26000).