Companies that create and maintain a lasting competitive advantage can be some of the best long-term investment opportunities you'll ever find. Although competition usually brings down most companies eventually, a few industry leaders manage to produce outstanding returns for years or even decades as they take full advantage of their business opportunities.

To invest in these market leaders, you've typically had to ferret them out and buy the stocks individually. But a new exchange-traded fund seeks to gather them up in one place for you. Let's take a closer look at the ETF and the stocks it invests in.

Crossing the moat
The brand-new Market Vectors Morningstar Wide Moat Research ETF started trading earlier this week. The ETF's methodology relies on what Morningstar calls its Economic Moat Rating, which looks for companies that will both earn outstanding returns on their capital and be able to sustain those high returns even in the face of competitors.

Morningstar identifies several ways that companies establish moats. In some cases, intangible assets like a powerful brand name create big profits. For others, cost advantages that result from either a favored way of doing business or economies of scale that smaller competitors can't achieve produce strong returns. And especially as the Internet has brought increasing attention on building networks of customers, companies that capitalize on network effects and that make it impossible or impractical to switch to other providers capture customers for the long run, building an ever-increasing competitive advantage over would-be disruptors in their industries.

Haves and have-nots
One interesting impact of using that definition to define the ETF's 20-stock portfolio is that some industries have disproportionately large representation in the ETF, while others get left out completely. In particular, technology, financials, and materials stocks get more weight, while consumer staples and telecom stocks have no representation within the fund.

It's hard to argue against some of the biggest companies in the ETF. Google and Cisco (Nasdaq: CSCO) are clear leaders in their respective tech fields, even if Cisco has faced increasing competitive pressure from its smaller rivals in recent years. Amazon.com has built an online-retail empire that seems insurmountable. And even though Exelon (NYSE: EXC) is far from the only utility company in existence, its particularly well-diversified generation capacity from sources including nuclear power plants as well as coal- and gas-fired production facilities give it an advantage that could assert itself more clearly once fossil-fuel prices start rising again.

But some of the other stocks in the ETF may raise some eyebrows. St. Joe Company (NYSE: JOE) owns a unique set of business assets, with huge tracts of Florida land that could eventually represent prime opportunities for development. Yet the real estate bust let the air out of the company's shares, and a year and a half ago, it found itself the subject of a major debate between institutional investors David Einhorn and Bruce Berkowitz. Similarly, both Merck and Pfizer (NYSE: PFE) appear on the list, despite the presence of numerous competitors in the pharmaceutical field that seem to have at least as promising pipelines for future development.

Moreover, the absence of other companies is also hard to explain. To produce more balance across industry sectors, consumer giants Coca-Cola and Procter & Gamble (NYSE: PG) seem like logical choices. Morningstar even uses Coca-Cola in its explanatory materials as an example of a wide-moat company, while P&G's billion-dollar brand dominance demonstrates the value of its intangibles as well as the economies of scale that allow it to serve customers around the world.

A good idea
Regardless of whether you agree with the Market Vectors ETF's particular choices, searching out companies with lasting competitive advantages can produce great results. Even if you don't invest in the ETF, you can use its picks as a great starting point for further research for your individual-stock portfolio.

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