California Code, Financial Code - FIN § 7503

Except as specified by the loan contract or by Section 2954.8 of the Civil Code, an association shall have no obligation to pay interest to the borrower upon funds credited to an impound, trust, or other type of account for payment of taxes, insurance, or other charges relating to the property, or to invest them for the benefit of the borrower, unless the funds have been placed in an interest bearing savings account under the terms of the loan contract.