National Investment Managers Inc. has acquired Benefits Dynamics Inc. for about $500,000 in cash and notes.

National Investment, New York, is a financial services firm consolidator that is buying pension plan administration, investment management and insurance businesses.

Before National Investment made the National Actuarial acquisition, it was administering 7,100 retirement plans with $6.8 billion in plan assets.

Benefits Dynamics, Cherry Hill, N.J., a firm that was founded in 1979, administers 200 retirement plans with about $200 million in assets. It also runs 100 Section 125 plans.

Jo-Ann Massanova, president of Benefits Dynamics, will stay with the firm after the acquisition, National Investment says.