26 CFR § 1.616-3
Time for making election with respect to returns due on or before May 2, 1960
June 25, 2020
In the case of any taxable year beginning after December 31, 1953, and ending after August 16, 1954, the income tax return for which is due not later than May 2, 1960, the time to deduct or defer development expenditures for such a year under section 616 (a) or (b) shall expire on May 2, 1960.