Gantt, 52, initially joined Fiserv in December 2000 and led the company's Insurance Solutions Group as President until early 2003. He then left Fiserv to become Chairman, President and Chief Executive Officer of Ephinay Corporation, a provider of outsourced finance and accounting services.

During his tenure with the Fiserv Insurance Solutions Group, Gantt led a successful expansion of the group's business into new industries such as health plan administration. The health plan administration segment later was spun off into a separate group called Fiserv Health and now represents about 25 percent of Fiserv's total revenues.

With his return to Fiserv, Gantt will lead an operating group that includes a significant portion of Fiserv's core processing offerings for banks, and also includes providers of electronic funds transfer services, risk and cash management software, document imaging software and customer contact management software.

"This is an announcement mixed with both delight and sadness," said Leslie M. Muma, Fiserv President and Chief Executive Officer. "We are thrilled to welcome Mike back to Fiserv. At the same time, we are losing an outstanding leader in Rod. His talent, wisdom and vision will be deeply missed, but we wish him well in this new endeavor."

Poskochil will continue as Chairman of the Fiserv Corporate Product and Technology Committee, an organization responsible for Fiserv's overall technology strategies, until a successor is named and will remain with the company during a planned transition period.

Norm Balthasar, Fiserv Chief Operating Officer, said Gantt returns to Fiserv with a wealth of business expertise - ranging from insurance technology to business process outsourcing to finance and accounting services.

"Mike's unique blend of experience will be a great addition to Fiserv," Balthasar said.

Gantt said Fiserv's people are its greatest strength, and that those people are making the company's future even more exciting than its past.

"Leaders like Rod have made Fiserv the outstanding company that it is, and positioned it for greater things to come," Gantt said. "I am very excited to be rejoining not merely a company that I admire, but one that I have come to realize is family to me."

Poskochil said he looks forward to slowing his pace and spending more time managing several personal business investments.

"I have devoted nearly my entire business career to Fiserv, so this was a very difficult decision for me because I believe this company is just a world-class organization" Poskochil said. "However, I now will have much more time to devote to my family, my other personal interests and my business investments."

As a group president, Gantt will be a part of Fiserv's Management Committee, a group that shapes much of the company's strategy and direction. Gantt will report directly to Balthasar.