Cal. Unemployment Insurance Code § 1093

In the event any employer shall fail to keep and furnish to the director, upon notice, any required records or reports necessary for a full determination, decision on appeal, or other proper disposition of any claim for benefits in any proceeding under this division, within such reasonable time as the director may by rule, regulation, or procedure prescribe, it shall be conclusively presumed that the claimant is entitled to the maximum total amount of benefits payable under this division unless it is established by other evidence which the director deems sufficient that a lesser total amount of benefits is properly due and owing to the claimant. If so established by other evidence upon default of the employer, after notice, such lesser total amount of benefits thus determined shall be conclusive. In all cases in which such presumptions shall apply, if the claimant has earned wages in employment for more than one employer during his base period, the accounts of the employer or employers who have properly kept and furnished the required records or reports shall not be charged with benefits in an amount exceeding that which such accounts would have been charged had the claimant been entitled only to benefits determined by the total of the wages earned and the number of calendar quarters worked for them and all benefits paid in excess thereof shall be charged solely against the accounts of the employer or employers who have failed to keep or furnish the required records or reports.