I would like to amend my 2015 return for an $8000 capital loss I did not claim in my 2015 1040. Must I submit a regular corrected schedule D with the 1040X?

Yes, you must provide a copy of all of the tax forms which are impacted by this change- The Schedule D and the source form to show the capital loss and the corrected 1040, although numerous other forms and schedules could be impacted by this change. For some, an amended return requires the attachment of quite a few forms.

In general, capital gains and losses are no longer directly reported on Schedule D. Stock sales, for instance, flow into Schedule D from Form 8949.

You cannot only send in a 1040-X, as that form won't show the capital loss transaction in any detail. If you are missing forms with the amendment, your refund may be held up.

If you follow the amend process for Turbo Tax 2015, all of these forms will be updated on your behalf.

Note: When you download our amend software, you will be able to add a sale of stock (even if this was not supported in Deluxe online last year). There's no need for you to do these forms by hand.

https://ttlc.intuit.com/questions/3410543