Example. Corporation Z, which keeps its books and makes its tax returns on the calendar year basis, filed its income tax return for 1956 on March 15, 1957, showing a tax of $100,000. At the same time it filed a statement under section 6164 extending the time for payment of the entire $100,000 on the basis of an expected net operating loss carryback from 1957. On April 10, 1957, the corporation filed a new statement indicating that the reduction, attributable to the carryback from 1957, in its income tax for 1956, would only be $80,000, and thus terminated the above extension of $20,000. The time for payment of such $20,000 may not be extended again, and such $20,000 is payable as if it were the tax for 1956 and Corporation Z had elected to pay such tax in installments. That is, $10,000 is payable on March 15, 1957, and $10,000 payable on June 17, 1957. Inasmuch as the March 15 date had already passed when the Corporation Z terminated the extension with respect to the $20,000, $10,000 is payable immediately upon such termination, and the other installment of $10,000 is payable on June 17, 1957. This example would also apply if the extension of time for payment of the $20,000 were terminated instead by the district director on April 10, 1957.
26 C.F.R. §1.6164-8