Check with your 401(k) plan administrator if they allow self-directed 401(k). With self-directed 401(k) you take your own investment decisions. Section 408 of the Internal Revenue Code permits individuals to use a self-directed retirement plan to purchase land, commercial property, condominiums, residential property, mortgages, trust deeds, real estate contracts or private placements and many other types of investments. However, you can not use the property for personal use or for the use of relatives.
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Your U.S. Tax Return: Elective Deferrals 401(k) Plans