CFR /  Title 20  /  Part 220  /  Sec. 220.29 Work that is considered substantial gainful activity.

Work is considered to be substantial gainful activity if it--

(a) Involves doing significant and productive physical or mental duties; and

(b) Is done or is intended to be done for pay or profit. (See Sec. 220.141 for a detailed explanation of what is substantial gainful activity.)