Value investing legend Benjamin Graham always stressed margin of safety above all else in making any investment decision. Regardless of the potential upside, like Graham, all investors should always be concerned with the downside. One way to for investors to protect themselves is seek strong, quality businesses with fortress-like balance sheets along with industry dominance.

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No Boundaries
Brazilian oil giant Petrobras (NYSE:PBR) is worth a closer look. The company offers investors a long-term play on oil and Latin America. In addition, one of the largest new potential discoveries of oil, the Tupi field, significantly involves Petrobras. As Latin America grows and develops, Petrobras benefits.

At a market cap of $120.96 billion, Petrobras is not going anywhere; at a P/E of 7.16, shares are not expensive at $19. Holding Petrobras for a number of years will in all likelihood deliver returns that meet or exceed the broad market. At the same time, investors can be comforted that Petrobras has the financial strength to weather the storm.

Developing Oil Plays
A "sister" company to Petrobras is PetroChina (NYSE:PTR), another wonderful business operating in the fastest growing economy in the world. There are always risks to investing in foreign countries like China and Brazil, but you mitigate those risks with dominant businesses like Petrobras and PetroChina. Both companies are held by many investment funds and highly regarded money managers. PetroChina commands more of a premium at a P/E of 11. At the height of the oil boom, both businesses were trading at twice today's multiples. Also, both companies pale in comparison with Exxon Mobil's (NYSE:XOM) market cap of $373 billion, but operate in countries that offer them the opportunity to become one of the largest oil companies in the world.

SEE: The Value Investor's Handbook

The Economics of Concrete
Vulcan Materials
(NYSE:VMC) is a leading supplier of infrastructure materials, namely concrete, asphalt and cement. As construction activity has fallen of a cliff, so has Vulcan's business. However, a basic understanding of the aggregates business shows why Vulcan will reward patience.

The weight-to-value ratio of Vulcan's products is high; in other words, transportation costs are relatively high. Customers always buy their products from the nearest supplier within a 25 to 30 mile radius. In other words, a Vulcan competitor 50 miles away that sells cheaper materials won't get the business because the extra transportation costs offset the savings.

Thus, companies with a wide network of distributors have a monopoly-like moat. In addition to Vulcan, Texas Industries (NYSE:TXI) is another supplier of aggregates with a strong moat. As well, the costs and time to establish a mine today is very prohibitive; concrete mines are very loud and dusty and no neighborhood or municipality really wants one. So companies that own existing mines are ahead of the game.

Bottom Line
One key in selecting investments is to really think about the business over a period of many years and ask yourself if you would like to be in that business. This metric is one that many value investors use, and as a result, leads to successful results.

SEE: Battered Stocks That Bounce Back