What's This Stock Really Worth?

Are you right 100% of the time?

If so, you'd better hope that there's no one out there just like you -- and that if there is, you never trade a stock with that person. Because if you do, one of you has to be wrong.

Whenever you trade a stock, you're disagreeing with the person making the trade with you. If you're buying, you think the stock is going up. The other side, of course, is selling, perhaps believing that the stock is headed downward.

Do you care what they think?
Expand these transactions over a larger scale, and you can see why the law of supply and demand more or less rules the trading floor. Too much supply? The price goes down. Too much demand? The price goes up.

And while each trade typically includes only an extremely tiny sliver of a company's total number of outstanding shares, the most recent trade directly affects the value of every share. In essence, a small sampling of opinions drives stock prices on a day-to-day basis.

That can be a scary realization, if you have your life savings invested in the market. But it's actually a huge opportunity for you to make more money in the long run.

Dig up the facts
Even though opinions drive daily stock moves, facts drive long-term valuations. When there's a disconnect between market opinion and financial fact, you can profit handsomely.

To do so, you need to get a handle on the financial facts that best indicate a company's real worth. While that's impossible to know exactly, you can make a pretty good educated guess, based on a combination of company projections, analyst estimates, and proven track records.

Once you collect the data you need, you can run it through a discounted cash flow (DCF) calculation to estimate the value of a company's stock. Here's a rough-cut analysis for a handful of fairly well-known firms:

Verify the variance
Most of the time, the market does a pretty good job of pricing a stock. In this particular case, only UnitedHealth and Amazon.com seem more than 35% out of line with my very rough DCF estimate.

In UnitedHealth's case, the discount seems to stem at least in partly from the very political nature of the health-insurance business. With several prominent presidential candidates espousing plans for government-run health care, private insurers like UnitedHealth may risk losing a large chunk of their businesses, or being heavily regulated.

On the flip side, Amazon.com looks a bit overvalued. Much of its premium seems to come from investors' belief that the online retailer finally seems able to profitably leverage its huge infrastructure investments. Whether or not that premium is justified depends largely on how well Amazon can keep growing incremental revenue without incurring more such costs.

So what?
If you pay fair value for a stock, you should end up earning the company's growth rate (plus dividends) over time. That's OK, but it won't help you beat the market by any significant margin.

When you pay less than fair value, you'll not only get a return alongside the growth rate, but also profit significantly when the stock rebounds to fair value.

In UnitedHealth's case, if the market decides that America won't accept a government-run health system, no matter who wins the White House, you'll earn that 39% gap bonus as it recovers. But you can do even better.

Take the case of the Nasdaq Stock Market (Nasdaq: NDAQ), originally selected for Motley Fool Inside Value in April 2007. As the largest all-electronic American stock market, the company has a tremendous competitive moat in terms of both operational and compliance costs. Better yet, at the time, its shares were tremendously undervalued, even if you assumed it couldn't grow as fast as the analysts were expecting.

As events unfolded and the investing world woke up to the value available right below their noses, its shares skyrocketed. As of this writing, Nasdaq has returned more than 60 percentage points since being selected for Inside Value.

Find the next Nasdaq
Unfortunately, thanks to that tremendous surge, Nasdaq's no longer the bargain stock it once was. The market, however, always offers some fire-sale opportunities, somewhere. To truly crush the market, you need to focus on finding those opportunities, wherever they may be. That's our tack at Inside Value. In addition to our own value picks, we also offer a DCF calculator for subscribers, to help you run your own calculations on stocks you've uncovered.

You can kick the tires on the calculator and take a look at all of our research and recommendations by joining the service free for 30 days. There's no obligation to subscribe. Click here for more information.

This article was originally published June 20, 2007. It has been updated.

At the time of publication, Fool contributor and Inside Value team member Chuck Saletta did not own shares of any company mentioned in this article. UnitedHealth is a Motley Fool Inside Value recommendation. UnitedHealth and Amazon.com are Stock Advisor picks. PPG Industries and GlaxoSmithKline are Income Investor selections. The Fool has a disclosure policy.