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 SodaStream International (NASDAQ:SODA) were going flat today, falling 26% after the company revised its full-year guidance downward.

So what: The maker of the countertop soda machine provided its preliminary results for last year, saying it now sees revenue of $562 million, below the $567.2 million it guided toward in its October earnings report. The shortfall in net income was even worse, as the company now expects adjusted profits of $52.5 million, versus former projections of $65 million, essentially even with a year ago. What gives? Profits tanked in the fourth quarter as costs rose. CEO Daniel Birnbaum said the results "reflect a challenging holiday selling season in the U.S. and several factors, including lower sell-in prices and higher product costs, a shift in product mix, and unfavorable foreign currency changes."

Now what: Notably, top-line growth was still solid and is tracking toward 29% on the year, but a dramatic drop in profits like this is definitely a concern. The change in product mix probably reflects greater relative sales of its low-margin starter kits, not a surprise for the holiday quarter, but the company had already seen a hemorrhaging of its consumable sales starting in the third quarter, when revenue from its flavor units rose just 7% and fell in the U.S., probably a reflection of competition in that category. As a SodaStream shareholder, I find this news disconcerting, but I think the stock got hammered a bit too hard here. This has always been a volatile stock, and Its management team said it was working to restore margins to historical levels. They have proved highly capable before, and the stock now trades at an average P/E of 16. For a company that just saw its top line grow 29% last year, that seems like a mistake.