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 Rent-A-Center Inc. (RCII +1.72%) are down some 14% today after briefly plunging by more than 17% in early trading. The rent-to-own operator's fourth-quarter earnings report, released after Monday's closing bell, showed Rent-A-Center missed both its top- and bottom-line targets.

So what: Rent-A-Center's fourth-quarter revenue of $797 million resulted in generally accepted accounting principles earnings of $0.48 per share and adjusted EPS of $0.50. While the company's adjusted EPS doubled from the year-ago quarter, Wall Street analysts had pegged Rent-A-Center to more optimistic targets -- the consensus for revenue had been $804.8 million, and Rent-A-Center's EPS was expected to come in at $0.63.

Rent-A-Center expects to earn between $2.05 and $2.30 in adjusted EPS for 2015 on full-year revenue projected to range from $3.25 billion to $3.35 billion. Both figures, particularly on the bottom line, fall short of what Wall Street wanted -- analysts expected Rent-A-Center to generate $3.34 billion in revenue and $2.48 in adjusted EPS.

Now what: Investors might have been more bullish on Rent-A-Center's results if the company's shares had not risen by nearly 50% over the past year before today's collapse, with its P/E rising to post-crisis highs. The company's EPS expectation for 2015 offers anywhere from 5% to 18% upside from 2014's adjusted full-year EPS of $1.95. Rent-A-Center expects its top line to grow primarily due to new store openings -- its core same-store sales are expected to range from a decline of 1% to a gain of 1%, averaging out to no growth at all.

Rent-A-Center's P/E is still very close to 20 after today's crash, a level it has only touched twice since the start of this century. The first time that happened, Rent-A-Center grew its way out of high valuations, but the second time it suffered through a financial collapse with the rest of the economy. Since Rent-A-Center doesn't expect to post the same growth rates that drove its P/E down in the early aughts (its EPS nearly tripled from the end of 2001 to the end of 2002), it might be best for shareholders to wait for a slide back to lower valuations before capitalizing on today's disappointment.