California Code, Government Code - GOV § 53654

(a) The depository may add securities to the pool or substitute securities of equal value for those in the pool at any time, but shall not interchange classes of security, as defined in Section 53632.5, without prior approval of the treasurer.

(b) Withdrawal of securities from the pool without replacement at equal value may be ordered only by two duly authorized officers or employees of the depository who satisfy the requirements as may be set by the administrator.

(c) The agent of depository is responsible for the safekeeping and disbursement of securities placed in its custody by a depository.  It shall release securities only upon presentation by the depository of the most reasonably current statement of the total deposits subject to this article held by the depository, such statement to be verified and countersigned by two duly authorized officers, other than those who ordered the withdrawal of securities.  A copy of this statement shall be forwarded to the administrator concurrently by the agent of depository.