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 daily deal site Groupon (NASDAQ:GRPN) jumped as much as 15% following the disclosure from investment firm Tiger Global Management that it purchased a 9.9% stake in the company.

So what: According to the SEC filing, Tiger Global Management has acquired an additional 63.7 million shares of Groupon during the latest quarter as the previous SEC filing noted just a 1.3 million share position. This purchase comes just two weeks after Groupon reported third-quarter results which showed a 32% increase in revenue, breakeven EPS, and total cash of $1.2 billion with no debt.

Now what: I'm not quite sure what's in the water at Tiger Global Management, but please keep it out of my drink! Groupon's revenue growth and cash position are enough to give bottom fishers a glimpse of Groupon's potential, but the company's slowing growth forecast and inability to consistently turn a profit gives credence that the business model may be flawed. Despite holding 49% market share, limited barriers to entry have allowed Google through its maps application, Microsoft through its MSN offers, and through its $150 million investment in LivingSocial to join a very crowded daily deal market. Not to mention that Groupon's accounting has been sketchy at best, which is what landed Andrew Mason on my list of worst CEO nominees in 2012. In short, I wouldn't let today's pop cloud your better judgment.

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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.