Administaff Inc. (NYSE: ASF), the largest PEO by revenue, reported first-quarter revenue edged down 0.9% to $457.7 million from $462.0 million in the first quarter of last year.

The Kingwood TX-based professional employer organization said the average number of worksite employees paid per month during the first quarter fell 7.8% from the first quarter of last year to 103,009. However, revenue per worksite employee rose to $1,481 per month in the first quarter -- up 7.5% from the year-ago quarter.

First-quarter gross margin narrowed to 15.9% from 18.1% in the first quarter of 2009.

Net income fell to $2.3 million in the first quarter, down 71.8% from the same period last year.

Administaff Inc. (NYSE: ASF)
For the first quarter ended March 31, 2010, compared with the same period in 2009.
Revenue: $457.7 million, -0.9%
Net loss: $2.3 million, -71.8%