Eubank (plaintiff), a life-insurance agent, was promised future commissions on the renewal of insurance policies he initially sold. The value of those commissions would depend on the premiums eventually paid on the renewed policies by policyholders. In 1924 and 1928, Eubank assigned the rights to two of his commissions to a trustee. The trustee received the two commission payments in 1933. Guy Helvering, the commissioner of internal revenue (commissioner) (defendant), determined that Eubank’s 1933 federal tax return should have included the two commissions as taxable income. Eubank petitioned the Board of Tax Appeals (Board) for review. The Board sustained the commissioner’s determination, and the United States Court of Appeals for the Second Circuit reversed the Board’s decision. The United States Supreme Court granted certiorari.