From May 25, 2011, Jon S. Fossel, Chairman of the Board, speaks to media after an annual meeting held at the UNUM headquarters in downtown Chattanooga.

Unum Corp., Chairman Jon S. Fossel, 69, is retiring as non-executive chairman of the company's board of directors.

William J. Ryan has been named non-executive chairman of the board, succeeding Fossel. The transition will take effect on September 30, 2011, when Fossel marks five years of service as chairman.

Fossel joined the board in 2002 and has served as non-executive chairman since October 1, 2006. He will provide consulting services to the company after his retirement. Ryan, 67, joined the board in 2004 and is currently chair of the Governance committee and a member of the Finance committee. He retired in 2009 as chairman of TD Banknorth Inc. Previously, he was president, chief executive officer and a director of TD Banknorth Inc. Ryan is also currently a director of Wellpoint, Inc.

"Consistent with my belief that board chairs should rotate periodically, I had indicated to the board earlier this year that I did not intend to serve more than five years as chairman," Fossil said in a statement Wednesday. "I have decided that this would also be a good time for me to step off the board. The company has achieved a remarkable turnaround, and I am confident it is well positioned for the future."

Ryan called Unum "an exceptional organization with a track record of outstanding performance, and I look forward to working with our strong board and management team to continue to create value for our shareholders."

Since 2006, Unum's operating earnings per share have grown at a compound rate of 11 percent and its stock price has outperformed the S&P 500 and the broader stock market. Unum has also increased its dividend three consecutive years and has completed or announced more than $2 billion in share repurchases since 2008.