California Unemployment Insurance Code Section 455
The director may enter into reciprocal arrangements with authorized agencies of other states or of the Federal Government, or both, whereby: (a) Potential rights to benefits accumulated under the unemployment compensation laws of one or more states or of the Federal Government, or both, may constitute the basis for the payment of benefits through a single appropriate agency under terms which the director finds will be fair and reasonable to all affected interests and which will not result in any substantial loss to the fund. (b) Wages or services in employment subject to an unemployment compensation law of another state or of the Federal Government shall be deemed to be wages in employment for employers for the purpose of determining an individual`s rights to unemployment compensation benefits under this part, and wages in employment for employers as defined in this part shall be deemed to be wages or services on the basis of which unemployment compensation under the law of another state or of the Federal Government is payable, but no such arrangement shall be entered into unless it contains provisions for reimbursements to the Unemployment Fund for such of the unemployment compensation benefits paid under this part upon the basis of such wages or services, and provisions for reimbursements from the Unemployment Fund for such of the compensation paid under such other law upon the basis of wages for employment as defined in this part as the director finds will be fair and reasonable to all affected interests. Reimbursements paid from the Unemployment Fund pursuant to this subdivision shall be deemed to be unemployment compensation benefits for the purposes of this part. The director may make to other state and federal agencies and receive from such other state or federal agencies reimbursements from or to the fund, in accordance with arrangements entered into pursuant to this subdivision.