(1) Interest paid on a constituent services account established under Title 13, chapter 37, part 4, MCA, 13-37-240, MCA, and the rules in this chapter, may be received and used to provide constituent services if:

(a) the interest is deposited directly into the constituent services account;

(b) the interest is paid by a bank, savings and loan, credit union, brokerage firm, or other financial or investment entity subject to regulation by the state of Montana or an agency of the United States government; and

(c) the interest paid is the entity's prevailing money market, savings, or certificate of deposit rate paid to other investors or depositors with similar interest bearing accounts.