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 Monolithic Power Systems (Nasdaq: MPWR) cratered today to the tune of 13.3% below last night's closing price at the worst.

So What: The maker of power-handling semiconductors fell just short of analyst targets in the third quarter, but followed up with thoroughly disappointing guidance for the next period. Management blames the upcoming shortfall on a one-two punch of high distributor inventories and weak end-customer demand.

Now What: We've seen fourth-quarter warnings from a plethora of high-tech businesses lately, but none from direct Monolithic competitors such as Texas Instruments (NYSE: TXN), Analog Devices (NYSE: ADI), or STMicroelectronics (NYSE: STM). This could be a harbinger of a new wave of soft-business warnings. If so, you have plenty of leeway to do something about it because this report didn't damage share prices of any of Monolithic Power's rivals today.

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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.