Ask a Fool: I Sold Stocks at a $10,000 Loss in 2019 -- Can I Write It Off?
First, I'd ask whether you had any capital gains for the year -- that is, other investments that you might have sold for a profit. You can use capital losses like yours to offset capital gains, with no limitation. Alternatively, if you own any stocks that you've been thinking about selling at a profit, but have been hesitant because of capital gains taxes, now might be a good time to do it. For tax purposes, you can use your $10,000 in losses to negate the profits you made.
On the other hand, if you don't have any capital gains to offset, you can still deduct investment losses from your other taxable income -- but only to a point.
Specifically, you can only use up to $3,000 of your investment losses as a deduction. Any excess can be carried over to the next tax year.
Source Fool.com