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 consumer brands specialist Prestige Brands (NYSE: PBH) were getting the red carpet treatment from investors today as they rose as much as 25% in intraday trading after the company bought 17 consumer brands from GlaxoSmithKline (NYSE: GSK).

So what: When there's an acquisition taking place involving publicly traded companies, generally the target's price will spike and, if it does anything, the acquirer's stock may fall. That was hardly the case today as Prestige's stock shot up after it announced it is spending $660 million for 17 over-the-counter health-care brands from GlaxoSmithKline. Among the brands purchased were Goody's, Ecotrin, Beano, Tagamet, and Sominex.

Now what: In the company's press release, Prestige CFO Ron Lombardi said the acquisition will be accretive to fiscal 2013 (which begins in April 2012) and that it will also improve "overall gross margin and EBITDA profiles" as well as "increase ... our free cash flow." From a shareholder's perspective, that hardly sounds like a darn good deal.

Of course with shares up substantially today, an increase in the overall value of the company due to the acquisition may have been quickly factored in. Also, it's notable that this is the largest asset purchase Prestige has ever undertaken, so investors will want to keep an eye out for any hiccups in the process.

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This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.