The Internal Revenue Code does not describe what a self directed IRA can invest in, only what it cannot invest in. Internal Revenue Code Sections 408 & 4975 prohibits Disqualified Persons from engaging in certain type of transactions.
Internal Revenue Code Section 4975(c)(1)(C) states that the direct or indirect furnishing of goods, services, or facilities between an IRA and a “disqualified person” would be considered a prohibited transaction. Thus, if a disqualified person, such as the IRA holder, serves as a real estate broker or listing agent on a transaction involving retirement assets, such as a self-directed IRA LLC, the payment of commissions/fees would violate Internal Revenue Code Section 4975(c)(1)(C) and would, thus, be considered a prohibited transaction.
If you are a real estate agent and will be using a self-directed IRA to make real estate investments, make sure you nor any other disqualified person does not serve as real estate agent or listing agent on the transaction. Furthermore, it is crucial that no disqualified person benefits personally either directly or indirectly from the IRA transaction. Thus, it is important that regardless of how the transaction is being structure, no disqualified person is placed in any position to benefit personally from any IRA investment.