In the case of Helvering v. Independent Life Ins. Co. (292 U.S. 371 (1934)), Independent owned a building.
They rented out part of the building and used the rest of the building for
themselves. The IRS wanted Independent to calculate how much money they could
have made by renting out the part of the building they were using themselves,
and pay taxes on it. However, the US Supreme Court found that the rental value
of a building used by the owner does not constitute income within
the meaning of the 16th Amendment.