Thanks. Allow me to construct a numerical example to clarify my situation.
Case 1. In tax year 2001, suppose I lost $80K when an Internet startup went bankrupt and claimed $3K as net capital loss in that year's f1040 and carried forward the rest. IRS p550 says "If part of the loss is still unused, you can carry it over to later years until it is completely used up." But I goofed up and did not claim net capital loss of $3K until now. (a) Your reply below says "all others are lost." Does this mean that I have lost $3K net capital loss carryover for each year from 2002 to 2016, which amounts to $45K (=3*15 years).? (b) If I have lost the net capital loss carryover for those 15 years, then do I need to amend my tax returns for those 15 years? (c) Your guidance says "Only the 2017 - 2019 returns can be amended to get the refund." This implies that (i) I can amend tax returns for 2017-2019 to harvest $3K for each year, and (ii) going forward I can continue to claim $3K each year from 2020 until the original $80K is exhausted. Is that correct?
Case 2. Instead of $80K in Case 1, suppose I lost only $48K. In this scenario, your "all others are lost" would suggest that I cannot claim any net capital loss carryover. Is that correct?
Appreciate your continued guidance.
