The 62-year-old chief executive officer of Great-West Lifeco U.S. Inc. catapulted his firm to the No. 2 spot among 401(k) providers with last month's acquisition of JPMorgan Chase & Co.'s recordkeeping business. Reynolds said his goal is to go after the top spot, occupied by his former employer Fidelity, where he was once chief operating officer.

"I'm very hungry to be the best," Reynolds, a West Virginia native who goes by Bob, said in an interview last month. "I know the business so well."

By expanding the retirement business, Reynolds is adding stable and recurring revenues and the possibility to sell more products to savers, a rationale that helped Fidelity diversify as clients scaled back purchases of traditional active mutual funds. His ambitious plan puts Reynolds in direct competition with Boston-based Fidelity, which he left in 2007 after being passed up for the top job at the family-owned retail-investing giant.