The fluctuation in the overall account value  has nothing to do with a tax return ....the account had earnings and  you pay taxes on the earnings in the account even if you do not take that money out of the account.  Ask your broker to explain it to you if you need more help. 

thanks. Sounds like, even if an account shows a tremendous loss in value, earnings (per 1099B & Div) are taxed.  There are no additional tax forms for making adjustments and showing loss in account value.  Insult on injury for 2018 :(

For tax purposes, the $2000 loss in value is an "unrealized capital loss". Until you actually  sell the the shares and "realize" the loss (or gain), you have nothing to report on your tax return.

If you have a 1099B for sales make sure you are only paying tax on the just the Gain and you can deduct any losses (from actual sales).  So make sure you enter your cost to figure the gain or loss.

If you have a net loss for the year you can only deduct 3,000 (1,500 MFS) max on your tax return.  The rest you have to carryover to next year.  You have to report the carryover every year until it's used up.  You can't skip a year.  

Ya'll, thanks so much. You helped me a lot.