The list of largest PEO firms was released today by Staffing Industry Analysts. The annual list includes all staffing firms with $50 million or more in 2011 U.S. staffing revenue. Here are the top three largest PEO firms in the U.S.:

• Insperity, 2011 U.S. staffing revenue $1.98 billion, market share 18 percent
• Automatic Data Processing, 2011 U.S. staffing revenue $1.65 billion, market share 15 percent
• Oasis Outsourcing, 2011 U.S. staffing revenue $420 million, market share 4.0 percent

Corporate members of Staffing Industry Analysts can download the full report by clicking here.