carryback of short-year net operating loss

If a C corporation that has a July year-end files a short-year return from 8/1/20 - 12/31/20 reporting an NOL and converts its tax year to calendar year end by filing Form 1128, can that loss be carried back to 7/31/20, 7/31/19, 7/31/18, 7/31/17, 7/31/16 tax years?

The following is from Checkpoint. Hope it will help you.

Short Period NOLs Due to Accounting Period Change

Generally, when a taxpayer changes accounting periods, a tax year of less than 12 months will result from the change. If the corporation has an NOL for the short period, the NOL may not be carried back but must be carried forward beginning with the first tax year after the short period. However, if the short period NOL is (1) $50,000 or less, or (2) less than the NOL that would have resulted for a full 12-month period beginning with the first day of the short period, the NOL must be carried back or carried forward as prescribed by IRC Sec. 172 (Rev. Proc. 2003-34).

Rev. Proc. 2003-34 also specifies that the taxpayer must wait until a full 12-month period has expired to determine whether it qualifies to carry back a short period NOL under the second exception mentioned in the previous paragraph.

Example 17B-3: NOL carryback following a change in tax year.
Jettex, Inc. has requested a change of accounting period that will result in a short tax year of four months. During this short period, Jettex has generated an NOL of $90,000. An NOL of $140,000 would have been incurred in the 12-month period beginning with the first day of the short period.

Since the NOL is greater than $50,000, it does not meet the first exception for carrying back a short period NOL. However, Jettex meets the exception allowing the NOL to be carried back if the loss is less than the NOL that would have been incurred for the full 12-month period beginning with the first day of the short period. Therefore, Jettex will be allowed to carry back the short period NOL of $90,000 in accordance with IRC Sec. 172. However, Jettex will have to wait until this full 12-month period has expired to make the determination of whether it qualifies under this exception. If it does not want to carry back the loss, it can elect to forgo the carryback period—see the discussion of this election later in this key issue.

I'm not sure if that is applicable now that we have a 5 year carryback period.

Rev. Proc. 2003-34. I think the right cite is 2006-45. But the essence of what Checkpoint says looks right. It's here in 6.06. https://www.irs.gov/pub/irs-drop/rp-06-45.pdf. And that's only for an automatic change. I assume they'd impose a similar requirement for one that seeks approval.

I'm not sure if that is applicable now that we have a 5 year carryback period.. I don't think it's changed.