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 used and salvaged vehicle auctioneer KAR Auction Services (NYSE: KAR) sank 14% on Wednesday after its second-quarter results disappointed Wall Street.

So what: While KAR lost $14.3 million due to an early debt payoff, its revenue for the quarter -- $470.6 million versus the analyst consensus of $488 million -- is likely the more disappointing number for investors. In fact, KAR's top-line remained flat year-over-year, suggesting that the downturn in the auto industry continues to weigh heavily on used car volumes.

Now what: I wouldn't be so quick to pounce on today's plunge. "We anticipate that supplies of used cars at auction will remain tight for the remainder of the year," said KAR CEO Jim Hallett, "and there is no assurance that the strong performance at Insurance Auto Auctions and [Automotive Finance Corp.] will continue for the remainder of the year and offset the impact of these lower volumes." When you couple that not-so-great outlook with historically low returns on capital relative to close rival Copart (Nasdaq: CPRT), KAR seems like an easy pass.

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