Ohio Rev. Code § 3307.151
The state teachers retirement system shall make no investments through, purchases from, or otherwise do any business with any individual who is, or any partnership, association, or corporation that is owned or controlled by, a person, who within the preceding three years was employed by, an officer, or a board member of the system or in which a person, who within the preceding three years was employed by, a board member of, or an officer of the system holds a fiduciary, administrative, supervisory or trust position, or any other position in which such person would be involved, on behalf of the person's employer, in decisions or recommendations affecting the investment policy of the system, and in which such person would benefit by any monetary gain.
R.C. §3307.151