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 Nationstar Mortgage (NYSE:NSM) declined 17.2% on Thursday after the residential mortgage servicer announced third-quarter results that included a laundry list of negative surprises, including an earnings miss and slashed earnings guidance for 2013 and 2014.

So what: Nationstar Mortgage's posted earnings per share of $1.08 (ex-items), a 14% shortfall relative to analysts' forecast for $1.26. The company also took an axe to its 2013 earnings guidance, bringing the range down from $4.05-$4.75 to $2.65-$3.10. Worse still, it did a similar job on 2014 guidance, with a new range of $4.50-$6.00, compared to the prior range of $6.45-$7.50.

Nationstar Mortgage also announced that it is selling its non-core wholesale and distributed retail origination channels to Stonegate Mortgage. As a result of the transaction and other downsizing measures, Nationstar's head count is expected to fall by some 1,100 employees.

Now what: Nationstar's negative earnings surprise follows Ocwen Financial's third-quarter earnings-per-share miss of 60%. As Bloomberg News commented today: "Mortgage origination and servicing companies including Nationstar and Walter Investment are facing increased competition amid falling new loan volumes and fresh rivals." Long-term investors who anticipate a turn in the cycle (i.e., capital to leave the sector and fees to firm up) may wish to begin looking at Nationstar Mortgage or one of its competitors; however, the prevailing wind is not favorable and riding out the cycle could require much patience, along with a tolerance for volatility.