Excerpt: SPBA's member Third Party Administration (TPA) benefits outsourcing firms administer the employee benefits of about 40% of all U.S. workers. Entities other than SPBA members performing TPA duties...such as insurance company Administrative-Services-Only( ASO) cover an additional estimated 12-15% of the U.S. workforce. Thus, about 55% of all U.S. workers' employee benefit plans are administered by some form of outsourcing TPA.  MORE >>