Other misses came on April 1, 2009, about a month after stocks had begun to rebound, with a wrong-way "sell" call on McLean, Virginia-based Capital One and a "neutral" rating for American Express Co.

Capital One more than tripled through June 14 of this year, beating the S&P 500 by 129 percentage points on an annualized basis. After an upgrade to "hold," it underperformed the index by 26 points. New York-based AmEx, the biggest credit-card issuer by purchases, almost tripled and was last year's top performer in the Dow Jones Industrial Average.

Wells Fargo

Wells Fargo & Co., the largest U.S. home lender, fared better than the indexes during the time Whitney urged clients to sell and worse after she upgraded the San Francisco-based company to "hold."

Discover Financial Services, the Riverwoods, Illinois-based payments network rated neutral in August 2009, has since outperformed the indexes and larger rivals Visa and MasterCard, the only two firms that have Whitney's highest rating of "buy." She called Visa her "single best buy" during an interview with Bloomberg Radio on May 4, 2010, about a week after the stock reached an all-time high.

Among the 13 other companies she covers, Whitney has one sell recommendation, on Atlanta-based SunTrust Banks Inc. She rates Jefferies Group Inc. "outperform," and Citigroup Inc. "underperform." She rates 10 companies "hold."

Since Whitney began covering Visa and MasterCard on March 10, the two companies have underperformed the broader market and the S&P 500 Information Technology Index.

Accurate Predictions

Whitney's accurate predictions have provided returns that diverged less from the S&P indexes than her wrong-way calls.

After missing most of the increase in Goldman Sachs shares, Whitney raised the company to "buy" on July 13, 2009, and held that rating for three months. The stock rose 25 percent, providing an annualized return that outperformed the S&P 500 by 42 percentage points, while underperforming the financials index by 28 points. She downgraded the stock to neutral on Oct. 13 of last year, and it has since underperformed both indexes.

Whitney's accurate calls include "neutral" or "hold" ratings on Morgan Stanley, JPMorgan Chase & Co., U.S. Bancorp and Pittsburgh-based PNC Financial Services Group Inc. Morgan Stanley has returned 3.5 percent on an annualized basis and JPMorgan 23 percent since she started coverage on the stocks on April 1, 2009, compared with 28 percent for the S&P 500.

Clients who took Whitney's advice on April 1, 2009, to sell Citigroup, the company that cut its dividend 11 weeks after she said it would, missed out on a 46 percent gain. The S&P 500 returned 45 percent and the financials index 61 percent.