The Charlotte bank said late Thursday that the board's lead independent director, Lanty Smith, had assumed the title, effective immediately. Thompson, who reports to the board, remains a director and maintains responsibility for running the nation's No. 4 bank by assets.

Splitting the chairman and CEO posts has long been a cause of corporate governance advocates, who argue it provides a stronger check on management. Wachovia had previously resisted calls to make the change, saying having a lead director was sufficient.

In a statement Thursday, Thompson, 57, said giving up the chairman post frees him to "focus 100 percent of my time and attention on guiding the company through the current environment."

The decision was made by the board at a meeting Thursday, spokeswoman Christy Phillips-Brown said.

Experts said the move could help assuage angry shareholders but wondered whether it would have much of an effect on the company's operations.

The change elevates a director who has stood behind Thompson in recent weeks -- and who also has faced criticism himself. The shift comes at a critical time for Thompson, the bank's CEO since 2000 and a fixture on the Charlotte civic scene.

At last month's shareholder meeting, he faced calls to resign, largely over the bank's ill-timed acquisition of mortgage specialist Golden West Financial in 2006. Since then, the bank has disclosed additional missteps, including a regulatory settlement for its ties to telemarketers. On Tuesday, the bank said its first-quarter loss had nearly doubled.

Asked whether the change was Thompson's idea, Phillips-Brown said the decision was made by the full board, of which he is a member. Asked about the timing, she said separating the two positions "is the right structure for the company at this time." No changes have been made to compensation, she said.

Thompson, who also holds the title of president, joins other bank CEOs to come under pressure during a credit crunch spurred by the nation's mortgage mess. At the extreme, counterparts at Citigroup and Merrill Lynch have lost their jobs.

Smith has said in recent weeks that Thompson has the board's full backing. The bank said neither was available for comment Thursday. Asked whether the move signaled any change in the board's confidence in Thompson, Phillips-Brown noted that he maintains all of his duties running the company.

Smith, too, has faced attack

In his role as lead independent director, Smith assisted the chairman, approved meeting agendas, served as a liaison between independent directors and ran any meetings in which the chairman wasn't present. Now, as non-executive chairman, he will be in charge of all board matters and preside over its meetings.

Smith has served on the board since 1987, taking the lead director spot in 2000. He is also chairman and CEO of a Raleigh merchant bank. While Thompson has absorbed most of the heat during the bank's recent travails, Smith also has come under attack.

Analyst Dick Bove of Ladenburg Thalman & Co. blasted him for comments to The Wall Street Journal that seemed to imply that shareholders should have suspected a dividend cut was coming last month, even though management had previously said no reduction was necessary. "It is the most outrageous statement I can ever remember made by a board member directly insulting shareholders," Bove wrote in a research report.

John Moore, an activist shareholder in Charlotte who has long advocated for a CEO/chairman split, on Thursday said he was delighted by Wachovia's decision. But Smith wasn't his first choice for the job.

"He's closely tied to Mr. Thompson, and does not represent a truly independent voice," Moore said.

Activists had called on the bank as recently as last year to divide the chairman and CEO roles, but management opposed the change and shareholders voted down the proposals. Shareholders at Charlotte-based Bank of America rejected such a split this year; the bank has a lead director.

Virginia-based bank consultant Bert Ely said Wachovia's move is not surprising because governance advocates have been pushing public companies to make the change. But he added- "The one thing I wonder about is to what extent it's partly due to the losses Wachovia has taken and concerns about its risk management."

In particular, he said investors are troubled by Tuesday's disclosure that the bank's first-quarter loss had jumped to $708 million because of writedowns related to insurance investments. The bank may disclose more on that issue in a filing today.

Charles Elson, director of the Weinberg Center for Corporate Governance at the University of Delaware, said that separating the CEO and chairman positions has become more popular in the past year, and that it's a good move for a company that's facing shareholder ire.

"When a company is going through severe problems and there is a crisis of confidence in the management, it makes sense," Elson said. "You want the board to be as effective a monitor as possible. Having the board chaired by the individual being monitored doesn't make a whole lot of sense."

Smith's changing of posts could be "totally cosmetic" or a real change that gives him a bigger role in devising bank strategy, said Paul Hodgson of The Corporate Library, a corporate governance research firm. He said the change didn't necessarily weaken Thompson's position at the company, but does allow him to share more blame.

Thompson, a company lifer, has served as CEO without being chairman in the past. He became CEO of predecessor First Union in April 2000 but mentor Ed Crutchfield held onto the post of chairman until March 2001. Bud Baker also served a stint as chairman after First Union merged with Baker's Wachovia later in 2001.