Large enterprise customers are embracing BPO as a way to improve HR performance, cut costs, and optimize HR administration on a global basis. To assess the state of the HR BPO market and see how the vendors stack up against each other, Forrester evaluated the strengths and weaknesses of top HR BPO providers across 34 criteria. The result: Accenture, ExcellerateHRO, Hewitt Associates, and IBM are leaders by virtue of extensive HR BPO capability and complementary service offerings. ACS, Convergys, and Fidelity Employer Services are strong performers — in particular, Convergys has emerged as a strong challenger by virtue of recent awards — most notably, its mega-contract at DuPont. Included in this report is an interactive vendor comparison tool that provides detailed services evaluations and customizable rankings.