Mark Fetting, CEO and chairman of asset manager Legg Mason, Inc., will step down at the start of next month, the Baltimore, Md.-based firm disclosed Tuesday.

Fetting, which has circled an Oct. 1 target to leave his current role, will be succeeded on an interim basis in his CEO capacities by Joseph Sullivan, its current head of global distribution. Alternately, W. Allen Reed, Legg Mason's lead independent director, will assume a temporary non-executive chairmanship spot, the Sept. 11 statement said.

In his comments, Fetting explained that "now is the right time for new leadership to take the baton and continue to move the company forward into the next phase of growth and development."

The firm with about $636 billion in assets under management as of July 31 said that its board has already taken steps to form a search committee "to consider both internal and external candidates and will be engaging a leading executive search firm to assist," the announcement listed.

It was highlighted, however, that Fetting will remain in a consultant capacity "through year end."

"Since early 2008, Mark Fetting has led Legg Mason through a very challenging period of turmoil in the global financial markets and major changes in the asset management industry," Reed explained. "During this period, he has been instrumental in reducing the company's cost structure, improving its balance sheet and liquidity, and positioning the company for future growth."

Previously, in February 2004, the money manager explained in a prior release that Fetting, who was then president of Legg Mason mutual funds, was appointed president of its asset management business.

Further information regarding the staffing change was not available as inquires sent to a firm spokesperson were not immediately returned.