Also, capital loss deductions are limited to $3,000 per year ($1500 if single), not 12k or 15k as someone else mentioned. If you have more than $3k in losses you can carry it over year to year.
This $3,000 limit applies to taxpayers who use the single, head of household, married filing jointly, or qualifying widow/widower filing statuses. Married people filing separately are limited to $1,500 per person on net capital losses.
Single Capital Loss is also $3000/yr:
>>Stocks gains and losses are taxed as "Unearned Income" and fall into several categories
---- short-term gain/ordinary dividend[add to you income and tax]
---- long-term gain/qualified dividend[taxed at a flat 15%]*
* assuming you make more than the standard deduction
https://www.investopedia.com/terms/u/unearnedincome.asp