At Fool.com, we believe in buying great companies for the long term. However, not every company commands a fair price, and many trade for far more than they're actually worth.

In these situations, investors actually have a chance to benefit from a stock's plunge. When shorting a stock, an investor bets that price of a stock will go down, and profits from any downward movement. The practice is risky, inviting unlimited losses while only providing limited upside. However, shorting wildly overvalued companies can also help balance your portfolio against the volatile market swings we've seen in previous years.

To find shorting candidates, we screened for stocks with a high percentage of their publicly traded shares sold short. One such stock is Cirrus Logic (Nasdaq: CRUS), with a current short interest of  10.35%. That's pretty high, but let's see how it compares to other companies in its industry:

Source: Capital IQ, a division of Standard & Poor's.

We consider short interest greater than 5% to be a warning sign. While plenty of great companies can carry high short interest, that red flag is your invitation to dig for troubling information that the company's buyers might be missing.

When evaluating short candidates, start by assessing their near-term financial health. To check on Cirrus Logic's immediate health, we looked at its current ratio, which simply divides its current assets by its current liabilities. The more assets a company has -- cash, inventory, and accounts receivable, among others -- the more easily it should be able to pay off its obligations in times of financial distress.

Cirrus Logic's ratio in this category is solid, currently standing at 4.77. We look for a current ratio greater than 1.0 and Cirrus Logic has consistently exceeded this level over time:

Source: Capital IQ, a division of Standard & Poor's.

Once we've assessed a company's short-term financial health, we can determine whether it's overstating its earnings. Earnings are meant to show a smoothed-out picture of a company's profit potential over time. However, they're prone to various assumptions and manipulations. Companies can aggressively recognize revenue, or show high earnings even while they pour excessive amounts of cash into capital expenditures that are slowly accounted for over time.

For this reason, it's best to compare free cash flow to earnings. Free cash flow accounts for the actual cash flowing out of or into a business, and then subtracts out actual capital expenditure costs over a given period of time. In the last 12 months, Cirrus Logic's cash flow has been $27 million, while its earnings were $56 million.

Cirrus Logic's free cash flow has consistently outperformed its earnings. That's a good sign, showing that the company isn't using any sleight-of-hand accounting to overstate its earnings potential.

Source: Capital IQ, a division of Standard & Poor's.

One last consideration for shorting a company is valuation. Excellent companies often trade for prices that their business's long-term outlook can't support. Think back to the dot-com bubble: While technology companies like Amazon.com would eventually produce large profits, at the time, they lacked business models and future earnings streams to justify their mammoth market capitalizations.

The PEG ratio is a simple measure of whether a company is excessively valued. It compares a company's P/E ratio to its estimated growth rate. We compared Cirrus Logic's expected P/E ratio for the next 12 months to its five-year estimated growth rate. As an investor, you'd look for companies trading at P/Es less than their growth rate. As the table below reveals,  Cirrus Logic currently trades at PEG ratio of 0.57.

Company

Forward P/E

5-Year Growth Estimate %

5-Year PEG Ratio

Cirrus Logic

14.30

25

0.57

NetLogic Microsystems (Nasdaq: NETL)

20.10

20

1.00

Silicon Laboratories (Nasdaq: SLAB)

14.49

20

0.72

Microsemi (Nasdaq: MSCC)

11.35

15

0.76

Power Integrations (Nasdaq: POWI)

16.45

15

1.10

Monolithic Power Systems (Nasdaq: MPWR)

11.62

20

0.58

Micrel (Nasdaq: MCRL)

11.22

15

0.75

Source: Capital IQ, a division of Standard & Poor's.

With a PEG ratio of less than 1.0, Cirrus Logic looks attractively valued relative to its expected growth. Anyone shorting the stock probably has other areas of concern.

The long road to superior shorting
Identifying good short candidates requires diligent research. More importantly, you've got to know where to dig into a company's financial statements. While the measures we showed above are a great start in searching for shorting candidates, red flags like accelerating revenue recognition, aggressive acquisitions to hide underlying financial weakness, and changes in reporting methods can only be spotted by carefully analyzing the notes that companies bury deep in their filings.

Finding these opportunities requires skill, but you can do it. That's why John Del Vecchio, CFA, a leading forensic accountant and The Motley Fool's shorting specialist, put together his detailed new report. It shows you how to spot five serious red flags that can help you detect time bombs in your portfolio, and lead you to the next big short. You can get the entire report free by clicking here, or by entering your email address in the box below.

Jeremy Phillips owns shares of no companies listed above. Silicon Laboratories is a Motley Fool Stock Advisor recommendation. Try any of our Foolish newsletters today, free for 30 days. The Motley Fool has a disclosure policy.