Cal. Civ. Code § 1810.11
The buyer may request, not more frequently than once a year, that the seller inform the buyer of the total amount of finance charges assessed on the account during the preceding calendar year and the seller shall provide that information to the buyer within 30 days of receiving the request, without charge.
If the buyer's request for the information is made in writing, the seller shall provide the information in writing, provided, however, that if the seller is required to furnish the buyer with a periodic billing or periodic statement of account or furnishes the billing or statement of account, the requested statement of finance charges may be furnished along with the periodic billing or periodic statement of account.
"Seller," for the purposes of this section, means a person engaged in the business of selling goods or furnishing services to retail buyers whose annual sales pursuant to retail installment accounts in California have exceeded one hundred fifty million dollars ($150,000,000) in the seller's last two consecutive years.
Ca. Civ. Code § 1810.11