In my taxable investment account will taking 20k in long term losses offset 10k in long term gains, and any of 10k in interest and 12k in dividends?

[tagteam]

In your hypothetical:

The $20k loss will be used to offset the entire gain of $10k. Up to $3k of the remaining loss will be used to offset all other income (which would include interest and dividends). The net loss balance of $7k will be carried forward to the next tax year.

[NCperson]

@Timbo99 the long term losses will certainly offset the long term gains.   otherwise, the losses can only offset up to $3000 of ordinary income (the interest and the dividends) each year.  In your example, the remaining $7000 of losses are carried over to 2024.