SEC Commissioner Resigns: Securities and Exchange Commissioner Richard Y. Roberts announced plans to join a small consulting and venture capital firm. Roberts, 44, will leave on July 15. As the SEC's lone Republican member, Roberts' departure will leave the five-member commission with three vacant seats. The White House has yet to formally nominate its choices to fill the seats. The nominees are subject to Senate approval. Roberts will become an executive vice president of Princeton Venture Research of Princeton, N. J., and will also serve as managing director of the firm's securities arm, PVR Securities.