California Code, Financial Code - FIN § 18325

(a) An industrial loan company shall not impose any charge on a periodic investment or thrift certificate, or on an investor in an account evidenced by such certificate, for the failure of an investor to invest, or for the late investment of, any agreed periodic installment investment into such an account.  An industrial loan company shall pay interest on periodic investment or thrift certificates at the same rate of interest per annum as is paid on investment or thrift certificates as to which an investor has not agreed to make periodic installment investments.

(b) As used in this section “periodic investment or thrift certificate” means an investment arrangement under which an investor undertakes to make periodic investments of a specified amount into one account, except, however, a periodic investment or thrift certificate shall not mean an impound account established for the purposes of the payment of taxes or other expenses and obligations in connection with a loan secured by real property, or a certificate of investment issued in connection with a loan pursuant to Section 18322.