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 power systems maker Vicor (Nasdaq: VICR) short-circuited today, dropping as much as 13.2% on very heavy trading volume.

So what: It would be unfair to say that Vicor's fourth-quarter report disappointed analysts, because I can't find evidence of a single firm following this stock, and management doesn't do guidance. Still, it's objectively bad news when the book-to-bill ratio lands at 0.66, far below the kingmaking 1.0 benchmark.

Now what: Vicor's sales are accelerating and margins are blossoming across the board, so it's not all bad news. Including today's drop, the stock has climbed more than 65% over the last year and it's also one of the highest-yielding dividend payers in the construction industry. Power-chip rivals Vishay Intertechnology (NYSE: VSH) and Power-One (Nasdaq: PWER) are climbing higher and faster but don't reward investors with a dividend. They're also followed by Wall Street (though lightly so in the case of Vishay), making Vicor the true dark horse in this market.

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