Is the party over for real estate investing?

No, we're not talking about regular people's homes. The biggest gains have come from so-called real estate investment trusts -- REITs for short.

REITs are companies that own a lot of different properties. Some REITs specialize in just one type of real estate (think apartments in California) while others own a bunch of different kinds of property such as hospitals, office buildings and malls. They make their money much like any landlord does -- by collecting rent.

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Investors have gobbled up REITs since 2009 for three reasons:

1) REITs trade like stocks. REITs give you real estate exposure a lot easier th