The securities commissioner, by rule or order, may require a minimum capital for registered broker-dealers not to exceed the limitations of Section 15 of the Securities Exchange Act of 1934, and establish minimum financial requirements for investment advisers, subject to the limitations provided in Section 222 of the Investment Advisers Act of 1940, which may include different requirements for those investment advisers who maintain custody of clients' funds or securities or who have discretionary authority over clients' funds and those investment advisers who do not.