Except as otherwise provided by law, the board and its officers and employees of the system shall not cause the system to engage in a transaction if they know or should know that the transaction constitutes a direct or indirect:

1. (a) Sale or exchange, or leasing, of any property from the system to a member or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, for less than adequate consideration, or from a member or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, to the system for more than adequate consideration.
2. (b) Lending of money or other extension of credit from the system to a member or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, without the receipt of adequate security and a reasonable rate of interest, or from a member or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, with the provision of excessive security or an unreasonably high rate of interest.
3. (c) Furnishing of goods, services, or facilities from the system to a member or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, for less than adequate consideration, or from a member, or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, to the system for more than adequate consideration.
4. (d) Transfer to, or use by or for the benefit of, a member or beneficiary of the Defined Benefit Program, as well as a participant or beneficiary of the Cash Balance Benefit Program, of any assets of the plan for less than adequate consideration.
5. (e) Acquisition, on behalf of the system, of any employer security, real property, or loan.