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: DeVry Education Group (NYSE:ATGE) stock is getting hammered on Feb. 6, down 17% as of 2:30 p.m.

So what: The company's Q2 earnings -- released after the market's close on Feb. -- came in 4% short of analyst estimates, and were down 12% from last year. Net sales in the quarter declined more than 1% from the year-ago period. This comes on the back of a relatively strong first quarter that had lifted the stock as much as 40% over the past year:

DV Chart

DV data by YCharts

The market also looks to be responding to statements from the earnings call that operating costs in the third quarter are expected to rise. CFO Timothy Wiggins said on the call:

We anticipate that operating costs will increase about 4.5% sequentially. About one-third of the increase will be driven by campus expansion at Chamberlain, about one-third is related to recent acquisitions in Brazil and about one-third driven primarily by an increase in DeVry University advertising expense, all to support future revenue growth.

Now what: The additional operating expense looks necessary in order to grow revenue, and the short-term hit to profits looks intended to pay off in the long-term by increasing enrollment, which will actually reduce operating expense as a percentage of revenue over time.

Will it pay off? Only time will answer that question. Attendance at DeVry University has recently been on the decline, while DeVry Brasil and Carrington are both growing attendance measurably.