The Investment Company Institute in Washington has appointed Peter J. Gunas III as director of retirement security and tax policy. He had been counselor to the executive director at the Pension Benefit Guaranty Corp.

Northern Trust Global Advisors in Chicago has appointed Joseph McInerney as chief operating officer. The company has also hired Darren Kimsey, Nicole Neubelt, and Kaz Sikora for the manager research team.

Craig Messinger has joined Pershing in Jersey City, N.J., as a managing director and member of the executive committee. He had been president of Boston-based Fidelity Capital Markets.

Rydex Investments in Rockville, Md., has hired Gregg A. Ruvoli as national sales manager. He was a national sales director at Lincoln, Neb.-based Allstate Financial.

Invest Financial Corp. in Tampa, Fla., has promoted Linda Sather to vice president of transition services. She had been vice president and sales review manager, responsible for the principal review of new accounts and trades for the company's non-OSJ offices and all producing OSJ managers.

Ibbotson Associates in Chicago has named Scott Wentsel senior portfolio manager for fund-of- funds investment management business. He was an executive director with Morgan Stanley in New York, where he worked on Van Kampen Investments asset management business.