Urban myth, clever advertising, or a remarkable betting coup on the movement of markets which turned a fiver into £3 million? The office junior who allegedly made a fortune by correctly betting on currency and stock market movements was the talk of wine bars in the square mile this week. The story (unsubstantiated) has it that a backroom boy at a major financial institution amassed a fortune by placing personal "spread bets" on movements in share and currency prices. He apparently started with a £5 wager on the French franc falling against sterling, graduating to predicting the fall-out on Tokyo and the bear run on the New York Stock Exchange.

Spread betting has become popular among high-rollers with time and money on their hands. This system involves gambling on whether the price of any given position will be higher or lower than the spread selected by the firm's experts. If right, the punter's stake is multiplied by the margin of the winnings, if wrong he, or she, has to pay up for every point outside the spread. A spokesman for City Index, the financial bookmaking firm which reputedly accepted the wager, said when constantly asked if it is true: "I just keep quiet and smile."