As investors, we need to understand how our companies truly make their money. A neat trick developed for just that purpose -- the DuPont Formula -- can help us do so.

The DuPont Formula can give you a better grasp on exactly where your company is producing its profit, and where it might have a competitive advantage. Named after the company where it was pioneered, the formula breaks down return on equity into three components:

Return on equity = net margins x asset turnover x leverage ratio

What makes each of these components important?

  • High net margins show that a company can get customers to pay more for its products. Luxury-goods companies provide a great example here.
  • High asset turnover indicates that a company needs to invest less of its capital, since it uses its assets more efficiently to generate sales. Service industries, for instance, often lack big capital investments.
  • Finally, the leverage ratio shows how much the company is relying on debt to create its profits.

Generally, the higher these numbers, the better. That said, too much debt can sink a company, so beware of companies with very high leverage ratios.

Let's see what the DuPont Formula can tell us about Cisco Systems (Nasdaq: CSCO) and a few of its sector and industry peers.

Company

Return on Equity

Net Margins

Asset Turnover

Leverage Ratio

Cisco

18.7%

18.9%

0.56

1.76

Hewlett-Packard (NYSE: HPQ)

21.6%

7.0%

1.05

2.96

Polycom (Nasdaq: PLCM)

6.1%

5.6%

0.83

1.32

Siemens (NYSE: SI)

14.3%

5.1%

0.74

3.59

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

Cisco achieves an attractive return on equity, with a lot of help from its very high margins. Cisco's asset turnover is the lowest here, and its leverage sits below those of some of its peers. HP scores an even higher ROE -- not because of margins, but rather because of its much higher leverage and asset turnover. Polycom and Siemens get much lower margins that Cisco, but Siemens really juices its ROE with high leverage while Polycom doesn't.

Using the DuPont formula can often give you some insight into how a company is competing against its peers and what type of strategy it's using to juice return on equity.

See a stock in this story you'd like to follow? Add it to My Watchlist, which will find all of our Foolish analysis on it.

We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Jim Royal, Ph.D., owns no shares of any of the companies mentioned. Polycom is a Motley Fool Rule Breakers pick. The Fool has created a bull call spread position on Cisco Systems. Motley Fool Alpha owns shares of Cisco Systems. Try any of our Foolish newsletter services free for 30 days. The Motley Fool has a disclosure policy.