Prohibiting Insider Trading Act This bill prohibits Members of Congress (or their spouses) from holding or trading certain investments (e.g., individual stocks and related financial instruments other than diversified investment funds, investments in the federal retirement savings plan, or U.S. Treasury securities). Generally, the prohibition applies seven days after the first day of a Member's initial term, though for current Members, it applies on the first day of the second session of the 118th Congress. Additionally, the prohibition does not apply to assets held in a qualified blind trust. Any profit stemming from a prohibited holding or transaction must be disgorged to the Treasury and may subject the Member to a civil fine. Additionally, a loss stemming from a prohibited holding or transaction may not be used as an income tax deduction. Each Member must submit an annual certification of compliance to the supervising ethics office. The office must publish each certification on a public website and periodically audit Members' compliance with the bill's provisions.