CA Ins Code §10123.147(b)

(b) If a complete claim, or portion thereof, that is neither contested nor denied, is not reimbursed by delivery to the claimant’s address of record within the 30 working days after receipt, the insurer shall pay the greater of fifteen dollars ($15) per year or interest at the rate of 10 percent per annum beginning with the first calendar day after the 30-working day period. An insurer shall automatically include the fifteen dollars ($ 15) per year or interest due in the payment made to the claimant, without requiring a request therefor.