William owns a building that is leased to Lester’s Machine Shop. Lester requests that William rewire the building for new equipment Lester plans to purchase. The wiring would cost about $4,000, but would not increase the value of the building because its only use is in connection with the specialized equipment. Rather than lose Lester as a lessee, William agrees to forgo one month’s rent of $1,000 if Lester will pay for the wiring. Because Lester does not want to move, he agrees. What amount, if any, must William include in gross income?
A partial list of research sources is

• Sec. 109
• Reg. Sec. 1.109-1
• CIR v. Grace H. Cunningham, 2 AFTR 2d 5511, 58-2 USTC ¶9771 (9th Cir., 1958)