Limitation on amount of gross income earned; “gross income” defined

The Commissioner of Social Security may prescribe the circumstances under which, consistently with the purposes of this subchapter, the gross income from a trade or business (including farming) will be considered sufficiently large to make an individual ineligible for benefits under this subchapter. For purposes of this subsection, the term “gross income” has the same meaning as when used in chapter 1 of the Internal Revenue Code of 1986.