Income so derived shall be referred to in this section as "includible farm rental income".
Example. A, an individual, owns a building containing four apartments. During the taxable year, he receives $1,400 from apartments numbered 1 and 2, which are rented without services rendered to the occupants, and $3,600 from apartments numbered 3 and 4, which are rented with services rendered to the occupants. His fixed expenses for the four apartments aggregate $1,200 during the taxable year. In addition, he has $500 of expenses attributable to the services rendered to the occupants of apartments 3 and 4. In determining his net earnings from self-employment, A includes the $3,600 received from apartments 3 and 4, and the expenses of $1,100 ($500 plus one-half of $1,200) attributable thereto. The rentals and expenses attributable to apartments 1 and 2 are excluded. Therefore, A has $2,500 of net earnings from self-employment for the taxable year from the building.
26 C.F.R. §1.1402(a)-4