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 (UNKNOWN:COUP.DL) plummeted on Tuesday by more than 25% after the company came up short of analyst expectations when it reported earnings Monday evening. A revenue miss combined with lackluster guidance sent the stock tumbling.

So what: Revenue increased by 14% year-over-year during the fourth quarter, far slower than the full-year growth rate of 32%. The company reported a net loss of $1.7 million for the quarter, down from a net gain of $1.5 million during the fourth quarter of 2013. One major driver of this decline was a vast increase in stock-based compensation, which rose from just $1.6 million to $7.8 million year-over-year.

The company expects revenue growth to slow going forward. For the first quarter, revenue is expected to land between $52 million and $54 million, well below an analyst consensus of $66 million, and about the same as the $52 million in revenue the company recorded during the first quarter of 2014.

Full-year revenue in 2015 is expected to grow by 24%-31%, driven by a strong second half. Growth of the Retailer iQ platform, a personalized digital coupon and analytics platform for retailers that launched in 2014, will be the main driver of this second-half strength, according to the company.

Now what: also announced a $50 million share buyback program, a somewhat baffling move. The company has never posted a profit, and even after the massive decline in the stock price today, the stock trades at about four times sales. The company does have about $200 million in cash left over from its IPO in 2014, but the idea of buying back shares less than one year after initially selling them to the public is strange at best and a desperate attempt to boost the stock price at worst. While the buyback may appear to be shareholder-friendly, it will also weaken the balance sheet at a time when the company has yet to figure out how to turn a profit.