This is more relevant for all of the top Japanese companies, as if you read the article, other major companies like Honda are being hit too. It's pretty simple, and works for the US too - When the Yen or Dollar are strong, the stocks sink. As someone who keeps an eye on the market on a regular basis, the Yen is trading pretty high, where the Dollar is not.
In the US, stocks are gaining rapidly due to the weak dollar, but in Japan stocks are sinking due to the high Yen. The most obvious companies are the ones in the top 5 in their respective countries. Sony might pare off small gains here and there, as their stock was valued quite lower than Nintendo's or Honda's.
Granted, recent news on PS3 pricecuts may boost Sony value too. That said, Nintendo's stock fluctuation is more based on the Yen moreso than anyone jumping ship on their stocks.







