California Code, Civil Code - CIV § 1802.7

“Retail installment account” or “installment account” or “revolving account” means an account established by an agreement entered into in this state, pursuant to which the buyer promises to pay, in installments, to a retail seller, his outstanding balance incurred in retail installment sales, whether or not a security interest in the goods sold is retained by the seller, and which provides for a finance charge which is expressed as a percent of the periodic balances to accrue thereafter providing such charge is not capitalized or stated as a dollar amount in such agreement.