if you have no prior 1256 gains there is no carryback. but you have to look at all 3 prior years. it goes to the 3rd first. if third np net 1256 gains no loss c/b. then 2nd prior year and if 1256 gain (see note) carryback may be available. any excess loss remaining goes to first prior year, if no 1256 gains no carryback.
so your carryback is limited to whatever can be used.
in the 2 nd prior year the amount that can be used is limited to the lesser of
1) net 1256 gain before the c/b
2) line 16 of schedule D before the c/b
Also, the carryback is allowed only to the extent it doesn’t increase or produce a net operating loss for the carryback year. The loss is carried to the earliest year first.
Make the election by checking box D and entering the amount to be carried back on line 6. To carry your loss back, file Form 1045, Application for Tentative Refund, or an amended return. Attach an amended Form 6781 and an amended Schedule D (Form 1040) for the applicable years.
On the amended Forms 6781 for the years to which the loss is carried back, report the carryback on line 1 of that year’s amended Form 6781. Enter “Net section 1256 contracts loss carried back from” and the tax year in column (a), and enter the amount of the loss carried back in column (b)
