June 19 (Bloomberg) -- The call sent Citigroup shares reeling -- down 11 percent in seven trading days. The analyst had downgraded the stock after citing investor dissatisfaction with Citigroup's senior management and saying Chairman and Chief Executive Officer Charles Prince should resign.

The analyst in question was Michael Mayo, a stock picker at Deutsche Bank -- not Meredith Whitney, the Oppenheimer analyst who has become the toast of Wall Street since her own report on Citigroup. She downgraded the stock to ``underperform'' from ``neutral'' on Oct. 31 after calculating in a research report that the bank's dividends for the third quarter of 2007 exceeded its profits. She also said the bank needed to raise $30 billion in capital.

Mayo, 45, gave his negative assessment of Citigroup more than two weeks before Whitney's. He downgraded the stock to a ``sell'' from a ``buy,'' the best call on Citigroup for the 12 months ended on March 31, according to data compiled by Bloomberg.

On the night of Oct. 11, Mayo got a call on his mobile phone while he was attending a New York Knicks basketball game. A colleague tipped him off that Citigroup had made some changes. In a press release, Prince had announced the departure of Citigroup trading chief Thomas Maheras, following almost $6 billion in losses and debt writedowns, and the promotion of Vikram Pandit, then chief of alternative investments, to head a new unit, the institutional client group.

That same night, online news stories quoted Citigroup Executive Board Chairman Robert Rubin as praising Prince and saying the CEO would be in charge of Citigroup for many years to come.

Longtime Prince Critic

Mayo, who has a Master of Business Administration from Washington-based George Washington University, was a longtime critic of Prince. The next day, he fired off a report downgrading Citigroup's stock.

``Our prior thesis was that either the company would perform well or top management would be replaced,'' Mayo wrote in his note. ``We feel that changes are needed in the office of the chairman.''

Of the two reports, Whitney's Oct. 31 call got much more publicity because it had a greater impact. Citigroup shares fell 8.1 percent the next day, their steepest decline since September 2002 -- compared with 3.4 percent the day after Mayo's downgrade -- and Prince resigned four days later. After Whitney's call, the stock fell 51 percent through June 18.

In January, Citigroup slashed its dividend, just as she said it should, to 32 cents a share from 54 cents. Pandit, who succeeded Prince in December, has raised $44 billion in new capital.

Whitney a Brown Grad

Neither Whitney nor Mayo would comment on the other's work. Both have continued to criticize Citigroup's management. Whitney, 38, who arrived on Wall Street 16 years ago after earning a history degree from Brown University in Providence, Rhode Island, holds out little hope that Pandit can solve the bank's myriad ills.

``It's an impossible feat,'' she says. ``It's not a case of changing the chef. The whole restaurant has to be shut down.''

Since Whitney's Citigroup downgrade, she's made dozens of appearances on cable TV business shows and has been quoted hundreds of times in the press.

``I love all the attention,'' she says. ``I think all the pressure is so much fun.''

Whitney's calls also get more attention from portfolio managers. ``She stepped out of the pack and, for that, she's a hero,'' says Michael Holland, who oversees more than $4 billion at Holland & Co. in New York. ``If she had been wrong, she'd have a black mark against her. It's good to have someone who takes the risk.''

CSFB Alumnus

Citigroup was not Mayo's first bold, contrarian call. In 1999, he was a banking analyst at Credit Suisse First Boston. At the height of dot-com mania in the spring of 1999, he issued a ``sell'' rating on all banking stocks when he saw that the merger boom was slowing and problem loans were growing.

The stocks did fall dramatically in the next six months. Mayo was fired in September 2000.

Credit Suisse declined to comment.

Mayo then spent six years as an analyst at Prudential Equity Group; he shifted to Deutsche in 2007 when Prudential closed down its equities trading desk.

To contact the reporters on this story: Kambiz Foroohar in New York at kforoohar@bloomberg.net. Yalman Onaran in New York at 6984 or yonaran@bloomberg.net.

Last Updated: June 19, 2008 00:15 EDT