"We're not buying the [S&P 500], we're buying the cheapest stocks in the index," he said from the Third Annual Forbes SHOOK Top Advisor Summit is Las Vegas.
Greenblatt said that from a bottom-up basis since 1990, the S&P 500 is in the 20th expensive percentile. Meaning, when compared to the last 28 years, the market's been cheaper 80 percent of the time and more expensive 20 percent of the time. But there are still name he likes despite pricey markets.
"Home Depot's is a duopoly. It's got an above-average business, trading cheaper than the market, huge returns on capital relative for the retail business. Lowe's is their only main competitor."
"The market overall's expensive, but this is a better business on average than the market," he added. "So it's a pretty great deal."
Greenblatt is also long aerospace and aircraft company Boeing, which he highlighted as a second duopoly. He added that its returns on capital are high for a capital-intensive business and air travel continues to grow over time. He likes Walmart, too.
Walmart "is a great business. They have -- if you want to talk about economies of scale -- if you're a retailer, that's the name of their business. They can do things cheaper, their buying power is better, they have loyal customers. They're in places that are convenient for consumers. They just built a business over time that just does things better."
The founder of Gotham Capital famously had annual returns of 40 percent from 1985 to 2005. He wrote the New York Times best-seller "The Little Book That Still Beats the Market."
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