What is a capital loss carryover?
If your capital losses exceed your capital gains, the excess is called a capital loss. The amount of any capital loss that can be claimed in any year is the lesser of $3,000, ($1,500 if you are married filing separately) or your total net loss as shown on line 15, column 3, of the Form 1040, Schedule D.
If your net capital loss is more than this $3,000 limit, you can carry the loss forward to later years. This loss is called your capital loss carryover.