Mass. Gen. Laws ch. 167, § 6: Manner and form of books and accounts; manner of safeguard and deposit of money and securities

Section 6. The commissioner may prescribe the manner and form of keeping the books and accounts of a bank and the extent to which they shall be audited. For a credit union, the commissioner may prescribe the manner of safeguarding its money and securities and may promulgate regulations under which a credit union may deposit its securities with savings banks, co-operative banks, trust companies or banking associations for safekeeping.