Can I carry forward a capital loss if I don't file a tax return?

[Jan1954]

My son had no earned income in 2018 with only minor dividends and interest but he did have a large capital loss from stock sales.  The net is a negative AGI.  So he does not have to file a tax return for 2018.  Will he be able to claim the capital loss from 2018 in 2019 (carry forward the capital loss from 2018 to 2019) if he does not file a 2018 tax return?

[VolvoGirl · Accepted solution]

Yes because he had a negative AGI.  But he should file 2018 to report the sales and establish the loss.  Or the IRS will see the sales and say they were all 100% gains and send him a bill.  I changed my mind, he SHOULD file.  I first thought he had prior losses to carryover from 2017.  

[Jan1954]

Thanks,
will file a tax return for 2018 to establish the loss (and carry forward).

[Anonymous]

definitely file to establish the capital loss carryover.  you see there's no way for the IRS to know that he didn't make a lot of money that was not reported to them.   also some people trade cryptocurrency on exchanges that do not report to the IRS so maybe he doesn't have a capital loss carryover.     it's cheaper to file now for free then in 2020 - Not free.  

[Jan1954]

Thanks,
will file a tax return for 2018 to establish the loss (and carry forward).