About 32% of the third-party administrators (TPAs) that run small and midsize defined contribution retirement plans expanded their client base between 2009 and 2010.

Analysts at Cerulli Associates Inc., Boston, published that finding in a summary of results from a poll of TPAs serving small and midsize plans.

The analysts found that 32% of the TPAs in that sector of the market increased the number of employers they served from 1% to 5% last year.

But the analysts also found that about 25% of the TPAs saw the number of employers they serve stay the same or up to 5%.

Other Cerulli findings:

- About two-thirds of the TPAs charge a monthly fee of $100 to $250 for a standard operating 401(k) plan.

- Asset control and influence are becoming more concentrated in the hands of specialists, and especially in the hands of registered investment advisors.

- Warren S. Hersch

Other retirement plan administration coverage from National Underwriter Life & Health: