What is the due date for filing an election to forgo the entire carryback period or forgo only section 965 years

The due date for filing an election to forgo the entire carryback period or to forgo only section 965 years depends on the taxable year in which the net operating loss (NOL) arises:

1. For an NOL arising in a taxable year beginning in 2018 or 2019, the election must be made by the due date (including extensions) for filing the taxpayer's Federal income tax return for the first taxable year ending after March 27, 2020.
2. For an NOL arising in a taxable year beginning in 2020, the election must be made by the due date (including extensions) for filing the Federal income tax return for that taxable year.

Once made, both elections are irrevocable.

Sources:
Rev. Proc. 2020-24
§ 965. Treatment of deferred foreign income upon transition to participation exemption system of taxation
§ 172. Net operating loss deduction
IRM Part 21. Customer Account Services. Chapter 5. Account Resolution. Section 13. IRC 965 Transition Tax Procedures - Accounts Management