Can a Trader Choose to Apply the Mark-to-Market Rule to Non-Section 1256 Contracts?

Yes, a trader who qualifies as a "Trader in Securities" (not just an investor) can elect to use the mark-to-market method under Section 475(f) for all their trading activities. This election applies to all securities and non-Section 1256 derivatives traded in the ordinary course of business.

The key benefit is that all gains and losses are treated as ordinary, not capital, bypassing the capital loss limitations.