Not until you file an amendment for 2016. If you do, you may receive an inquiry from the IRS.
You can deduct up to $3,000 in capital losses ($1,500 if you're married filing separately) per year. Losses beyond that amount can be deducted on future returns as a capital loss carryover until the loss is all used up.
You can file that amendment for 2016 to claim those additional capital losses by following the directions in the FAQ below:
https://ttlc.intuit.com/replies/5114064
