Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of commodity chip wrangler Diodes (Nasdaq: DIOD) are lighting up the board today, rising as much as 10% on moderately heavy trading volume.

So what: Analyst firm Collins Stewart says Diodes stands to gain business as gadget builders route their orders around damage from the earthquake and tsunami in Japan. The company has no manufacturing facilities in Japan and only minimal business exposure to that market in general.

Now what: What sounds like a reasonable investment thesis loses some of its power when you consider that Diodes is far from alone in its relative isolation from Japan. Head-to-head rivals Vishay Intertechnology (NYSE: VSH), ON Semiconductor (Nasdaq: ONNN), and Fairchild Semiconductor (NYSE: FCS) all have smaller revenue exposure to the Japanese market than Diodes does, and none of them have significant production lines in the country, either. Collins Stewart may very well be right on the money regarding Diodes' opportunity here, but you should also consider other competitors stealing business from Toshiba and company.

Interested in more info on Diodes? Add it to your watchlist.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.