California Code, Public Resources Code - PRC § 6301.6

If any funds are impounded pursuant to Section 6301.5 under the custody and control of the State of California, such impounded funds may be invested and reinvested by the Director of Finance in bonds or other obligations of the United States.  Such securities may be sold or exchanged by the Director of Finance if, in his opinion, such sale or exchange is in the best interests of the State, and shall be sold by him whenever, and to the extent, necessary to effect any required transfer or other disposition of the impounded funds.

Securities purchased or otherwise acquired under the authority of this section shall be deposited and held in the custody and safekeeping of the State Treasurer, in the name of the account in the fund from which the investments were made.

Interest earned or other increment derived from investments made pursuant to this section shall, on order of the State Controller, be deposited in the fund from which the investments were made to the credit of the account covering the impounded funds, in augmentation of such impounded funds.