Prince Alwaleed bin Talal is not deterred by Citi's nearly 90 percent stock slide. He plans to boost his stake to 5 percent from less than 4 percent, calling the bank's shares "dramatically undervalued." Of course that value approach has been exceedingly cruel to fund managers who were likewise convinced that the selling was overdone. That's how the likes of Bill Miller of Legg Mason got burned on Fannie Mae and other financial stocks.

John Roque, managing director and technical analyst at Natixis Bleichroeder, likens the bank stock swoon to other manias, suggesting there is still room for the group to decline. The S&P financial SPDR is down 70 percent from its peak. Other manias by comparison, Dutch Tulip Mania (1637), 90 percent peak-to trough decline; South Sea Co. (1720), 90 percent; Tokyo Real Estate (1989), 84 percent decline; and U.S. dotcoms (2000), 92 percent.

For more:
- here's a Reuters article on the prince
- here's a Tech Ticker article on bank stocks

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