Except as otherwise provided by law, the officers and employees of this system shall not engage in a transaction with regard to a tax-preferred retirement savings program if they know or should know that the transaction constitutes, directly or indirectly, any of the following:
(a) The sale, exchange, or leasing of any property from the program to a participant for less than adequate consideration, or from a participant to the program for more than adequate consideration.
(b) The lending of money or other extension of credit from the program to a participant without the receipt of adequate security and a reasonable rate of interest, or from a participant to the program with the provision of excessive security or an unreasonably high rate of interest.
(c) The furnishing of goods, services, or facilities from the program to a participant for less than adequate consideration, or from a participant to the program for more than adequate consideration.
(d) The transfer to, or use by or for the benefit of, a participant of any assets of the program for less than adequate consideration.