National Investment Managers Inc. has acquired Stephen H. Rosen and Associates Inc.[@@]

National Investment, New York, is a national pension plan administration and investment management firm.

Stephen H. Rosen, Haddonfield, N.J., is a retirement plan services and retirement planning firm that serves 550 plan clients in the Philadelphia area. The plans have a total of about $800 million in assets, according to National Investment.

Stephen Rosen, the actuary who founded the firm in 1982, is president of the American Society of Pension Professionals & Actuaries, Arlington, Va. He will be working for National Investment, National Investment says.