As an investor, it pays to follow the cash. If you figure out how a company moves its money, you might eventually find some of that cash flowing into your pockets.

In this series, we'll highlight three big dogs in an industry and compare their "cash king margins" over time, trying to determine which has the greatest likelihood of putting cash back in your pocket. After all, a company can pay dividends and buy back stock only after it has actually received cash -- not just when it books those accounting figments known as "profits."

The cash king margin
Looking at a company's cash flow statement can help you determine whether its free cash flow actually backs up its reported profit. Companies that can create 10% or more free cash flow from their revenue can be powerful compounding machines for your portfolio.

To find the cash king margin, divide the free cash flow from the cash flow statement by sales:

Cash king margin = Free cash flow / sales

Let's take Nike as an example. Over the past four quarters, the footwear giant generated $3.2 billion in operating cash flow. It invested about $335 million in property, plant, and equipment. To calculate free cash flow, subtract Nike's investment ($335 million) from its operating cash flow ($3.2 billion). That leaves us with $2.8 billion in free cash flow, which the company can save for future spending or distribute to shareholders.

Taking Nike's sales of $19 billion over the same period, we can figure that the company has a cash king margin of about 15% -- a nice high number. In other words, for every dollar of sales, Nike produces $0.15 in free cash.

Ideally, we'd like to see the cash king margin top 10%. The best blue chips can notch numbers greater than 20%, making them true cash dynamos. But some businesses, including many types of retailing, just can't sustain such margins.

We're also looking for companies that can consistently increase their margins over time, which indicates that their competitive position is improving. Erratic swings in margins could signal a deteriorating business, or perhaps some financial skullduggery; you'll have to dig deeper to discover the reason.

Three companies
Today, let's look at three utilities:

Company

Cash King Margin (TTM)

1 Year Ago

3 Years Ago

5 Years Ago

PG&E (NYSE: PCG)

-7.5%

-12.4%

-1.0%

11.1%

Edison International (NYSE: EIX)

-5.6%

-3.7%

9.0%

4.2%

Sempra Energy (NYSE: SRE)

-1.8%

-0.4%

5.2%

-2.4%

Source: Capital IQ; TTM = trailing 12 months.

The utilities industry is known for strong and regular cash flows, but as you can see here, capital investment has eaten up all operating cash flow and then some, in the trailing 12 months. Still, the regular demand that utilities enjoy allows these three companies to pay out above-average dividends even as they make sizable investments for the future.

The cash king margin can help you find highly profitable businesses, but it should only be the start of your search. The ratio does have its limits, especially for fast-growing small businesses. Many such companies reinvest all of their cash flow into growing the business, leaving them little or no free cash -- but that doesn't necessarily make them poor investments. You'll need to look closer to determine exactly how a company is using its cash.

Still, if you can cut through the earnings headlines to follow the cash instead, you might be on the path toward seriously great investments.

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Jim Royal, Ph.D., does not own shares in any company mentioned. Nike is a Motley Fool Stock Advisor recommendation. Try any of our Foolish newsletter services free for 30 days.

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