Sony's share price rose 6.7 per cent for three minutes because of an unfortunate blooper by an unnamed trader on the Tokyo Stock Exchange, according to a Bloomberg report. Finger trouble apparently caused someone to buy 900 million shares in the company, sending Sony surging upwards until the error was discovered.

The numbers are worth conjuring with. Sony's shares are around the Y10,000 mark, which is $100 a share. So if you bought 900 million shares in Sony, you'd be shelling out the non-trivial sum of $90 billion, ie. enough to buy maybe 15-20 3G European cellular licences, slightly more than IBM's gross revenues for 1999, almost as much as Lou Gerstner's stock options, or enough to keep The Blessed Bill Gates in charitable works for approximately six months (we made the last two up).

Unsurprisingly the goof was discovered quickly, and corrected. But as Bloomberg notes that Sony's stock price rose Y420 on the day, we calculate that the rogue trader missed out on a paper profit of approximately $3.8 billionby chickening out of being the mother of all day traders.

Nobody's putting their hands up to being the culprit, but Bloomberg says some traders are muttering about BNP Paribas Securities Japan Ltd. ®