Your IRA may not buy an investment from or sell an investment to a disqualified person as defined by Internal Revenue Code Section 4975. To do so is known as “self dealing”.

FREE Self-Directed IRA Rules Guide
Additionally, investments made with self-directed IRA funds must be at arms length, which is most often defined as a willing buyer and willing seller coming together with no undue influence from outside sources.
Disqualified Persons Defined
Disqualified persons are individuals or entities between whom or which an IRA is prohibited (absent a special exception) from engaging in any direct or indirect sale or exchange or leasing of any property; lending of money or other extension of credit; furnishing goods, services, or facilities; or transferring to or permitting the use of IRA income or assets.
- Fiduciaries (which in the case of a self-directed IRA includes you, as the IRA owner).
- The following family members of the IRA owner:
- Spouse;
- Parents;
- Grandparents and Great-Grandparents;
- Children (and their spouses);
- Grandchildren and Great-Grandchildren (and their spouses).
- Service providers of the IRA (e.g., IRA custodian, CPA, financial planner).
- An entity (such as a corporation, partnership, limited liability company, trust, or estate) of which 50% or more is owned directly or indirectly or held by a fiduciary or service provider; also a partner which holds 10% of a joint venture of such entity.
NOTE: The term “disqualified person” under the Internal Revenue Code Section 4975 does not include siblings (brothers and sisters) or aunts, uncles, and cousins of the IRA owner.