Top Stocks of the World's Top Billionaires

Updated from 7:03 a.m. EDT

With the publication last week of the Forbes list of the world's richest people, investors are taking a closer look at who the wealthiest billionaires are and, more telling, where they have their fortunes invested.

Bill Gates, founder of Microsoft (MSFT Quote), has dropped to third richest person, down from the top spot in last year's ranking. Warren Buffett, head of Berkshire Hathaway (BRK-A Quote), tops this year's list and Carlos Slim Helu, the Mexico-based telecom mogul, ranks second, according to the magazine.

Stockpickr.com tracks the stock portfolios of all three of these wealthy men, so let's take a peek at a few of their top holdings.

No. 1-ranked Buffett still likes homebuilding and improvement companies, such as Lowe's (LOW Quote). The North Carolina-based operator of more than 1,300 home-improvement stores in 49 states offers a price-to-earnings (P/E) ratio of 12, a P/E-to-growth (PEG) ratio of 1.1 and a yield of 1.4%.

Lowe's is also a holding of the American Funds Fundamental Investors Fund, a four-star Morningstar-rated fund managed by James Drasdo. The fund also owns shares of Suncor Energy (SU Quote), with a trailing P/E of 17.7, Deere (DE Quote), with a trailing P/E of 20, and Altria (MO Quote), with a trailing P/E of 16.

Carlos Slim holds a large position in America Movil (AMX Quote), the Latin American wireless and landline telecommunications company. Earnings for the latest quarter increased 47.6% on a 25% increase in revenue. The stock has a trailing P/E of 19, a PEG of 0.5 and a yield of 3.9%.

One hedge fund that also likes American Movil is SAC Capital, Steven Cohen's fund with $12 billion under management. It also owns shares of Wyeth (WYE Quote), a pharmaceutical company with a trailing P/E of 12, Cabot (CBT Quote), a specialty chemicals manufacturer with a trailing P/E of 16, and Albemarle (ALB Quote), a polymer and chemical producer with a trailing P/E of 15.7.

Bill Gates' investment vehicle is called Cascade Investments. One of its major holdings with a very favorable P/E ratio is Canadian National Railway (CNI Quote). The major transporter of petroleum, chemicals, metals, lumber, coal, grain, fertilizers and other products has a P/E of 12 and a PEG of 1.1.

Canadian National also shows up in Stockpickr's Top Dividend Increasers for the Week Ending Jan. 26. The stock offers a yield of 1.8%. This portfolio also includes Polaris Industries (PII Quote), with a trailing P/E of 12, Donaldson (DCI Quote), with a trailing P/E of 21, and Energen (EGN Quote), which has a trailing P/E of 14.

You can find the portfolios of Bill Gates, Warren Buffett and Carlos Slim Helu at Stockpickr.com.