If you are a trader in securities and you made a mark-to-market election, your gains and losses from securities and commodities trading activities are reported on Form 4797, rather than on Schedule D. When you make the mark-to-market election, each security you hold at year-end is considered to be sold and reacquired at its fair market value on that date.
All gains and losses from your securities trading are ordinary income and losses, instead of capital gains and losses. So the lower capital gain rates do not apply, but at the same time, you are not subject to the limitations on capital losses. And the wash sale rule does not apply, so as a trader, you could deduct a loss on a wash sale, instead of having to add a disallowed loss to the basis of the securities you purchase.