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 optical components manufacturer Fabrinet (NYSE: FN) look blurry today, fading as far as 20.7% on very heavy volume.

So what: Analyst firms Stifel Nicolaus and Morgan Stanley just downgraded Fabrinet from buy to hold. We don't have any detail on the reasons for these harmonized hits, but Fabrinet recently said that floods in Thailand are having a material impact on operations in that crucial manufacturing space; the downgrades are likely reactions to the bad news.

Now what: Just when you thought no company could suffer as much from the Thai disaster as hard drive maker Western Digital (NYSE: WDC), Fabrinet comes along with a bigger hit. I saw a buy-in opportunity in Fabrinet three months ago, but shares have fallen 41% more from the prices I saw then. This time, there's severe damage to the company's operations, to the point where large customer II-VI (Nasdaq: IIVI) points to Fabrinet's flooding as a limit on next quarter's results. Let's just watch this company for signs of recovery and rebuilding before taking any action.