Jul. 16--There is no doubt about it -- Wall Street investors just love an "investment guru", someone who manages to get it right at least once in their career. By contrast, in London investors have a sneaking regard for those tipsters with a good track record, but they are not held up to worship in the same way they are in the US.

Take, for instance, Meredith Whitney. Who? I hear you say. Well, she is one of Wall Street's best-known banking analysts, and has it all. A blonde with striking looks, a razor-sharp brain, and these days her own company -- Meredith Whitney Advisory Group.

Apparently, she called the top of the banking sector in October 2007, when she warned that the world's biggest bank, Citigroup, was about to implode with a $30 billion capital shortfall.

In those days, she worked for Canadian Imperial Bank of Commerce, and all she got for her efforts was abuse and even the odd death threat. Within days, an estimated £177 billion had been wiped off Wall Street. But last year when Citigroup eventually went cap in hand to the US Treasury in order to be bailed out, it established her as a top banking analyst -- one who was capable of single-handedly moving markets.

This week, she has been at it again. Only this time, she has been telling clients to fill their boots -- particularly in shares of Goldman Sachs, where she has at long last turned buyer, claiming there is scope for a 30 percent improvement.

Whitney popped up on the American business channel CNBC -- home of the money honey Maria Bartiromo -- to tell viewers to expect the "mother of all mortgage quarters". Once again she called it right, and the following day Goldman turned in second-quarter profits of $2.1 billion -- far in excess of even her own forecast.

Gamblers will always tell you it pays to back the in-form horse, and Whitney looks worth having a flutter on at the moment. But there are plenty of one-trick ponies littering the stock market -- many of whom got it right just the once and were never heard of again.

Take for instance Jim Rogers, who launched one of the world's fastest-growing hedge funds. Back in January, he told investors to sell sterling short because the UK economy was finished. After an initial sell-off, the pound is now trading back above the $1.40 to $1.50 level it traded at when he made that forecast. Rogers is now so disillusioned with the US economy he has moved to Singapore, where he waits patiently for the global economic recovery. Nick Knight was the equity strategist at Japanese stockbroker Nomura, and regularly moved markets.