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 Apollo Education Group Inc. (NASDAQ:APOL) were getting marked down today, falling as much as 10% after a disappointing earnings report.

So what: The University of Phoenix parent actually topped estimates on the bottom line, with a profit of $0.28 per share, better than estimates of $0.19, but sales came up short as revenue fell 18.6% to $679.1 million. Analysts were expecting revenue of $689 million. Enrollment fell at a similar pace as overall student count dropped 16.8% to 250,000 and new student enrollment dropped 16.5% to 32,500. The new student number is particularly concerning, as the figure is the best near-future indicator of an educator's performance.  

Now what: Without a turnaround in new student sign-ups, Apollo won't be able to deliver growing sales or profits over the long term. After a tough couple of years for the for-profit education sector, the stock had been making a comeback, more than doubling over the past 52 weeks, but today's report makes it clear that a sustained turnaround is unlikely anytime soon. I'd wait for new enrollment numbers to bottom out before getting in.