Someone tell me if I'm wrong, but this is what occurred to me. If you elect M-M, your federal tax rate could be as high as 39%, if you earn enough money. (A few hundred thousand, I believe.) If you don't file M-M you would pay a flat 28% rate for capital gains. That's an 11% difference you pay for electing. Of course, you'd be screwed by the wash sale rule, and couldn't deduct expenses, but it seems like at some income level it might be be advantageous not to elect.