Mystery day trader makes millions betting on Japanese markets

It was six minutes after the opening bell on February 4, and dozens of big-name stocks were still untraded in Tokyo. Telecommunications giant SoftBank was among those that had not budged. The offer price fell 5 per cent, then more, and still there were no takers.

Then an order was filled: 300,000 shares at 6,714 yen (HK$477) - worth just over two billion yen, or almost US$20 million. Other buyers followed, momentum built, and the stock ended the day as one of only two gainers in the Nikkei 225 Stock Average.

The man who made the market for SoftBank that winter morning was sitting in pyjamas in a bedroom cluttered with comic books.

Betting on rebounds was dangerous, but he'd watched SoftBank lose a fifth of its value over nine days, and a drop in the United States markets overnight had driven the shares even lower. The odds were tilting further in favour of a bounce, by his reckoning.

Ninety minutes later, he cashed out with a profit of 140.6 million yen. Then it was on to the next trade for the former video game champion and pachinko gambler who goes by the name CIS. The 35-year-old day trader says he made six billion yen, after taxes, betting on Japanese stocks last year.

During a decade of day trading, having started more or less from scratch, CIS has amassed a fortune that he says now exceeds 16 billion yen. In the process, he has become a cult figure among Japanese day traders, a tight circle of self-taught professionals who take pride in working one of the world's toughest markets. CIS has been the subject of much chatter and speculation. A Wikipedia page attempts to track his investment results.