Quote from kjkent1:
OK, I've looked up the relevant law, and I have what I believe is a fair interpretation.
1. The MTM allows the taxpayer to treat all trading gains/losses as if the trader had liqudated all positions for cash at the end of every tax year.
2. Making the MTM is not required in order to use Sched C, however, failure to make the election, or at least to change the taxpayer's accounting method, could be used as evidence to rebut the assertion that they are actually a trader. That is to say, if you're trading, then you should be looking to recognize short term income, by reconciling all short and long positions at the end of every trading day, and not making the election is not consistent with someone looking to recognize short term income. Rather, it is consistent with someone who is an investor, and who is seeking to defer taxes on long term investments.
3. 26 U.S.C. 475(f)(3) states: "The elections under paragraphs (1) and (2) may be made separately for each trade or business and without the consent of the Secretary." This actually indicates that the trader has no legal obligation to inform the IRS commisioner of the change in accounting, because if the failure to notify the IRS of one's making the election is sufficient to invalidate it, then that would be the exact equivalent of having to obtain the IRS commissioner's advance consent. Moreover, it appears that if the taxpayear files a return using MTM accounting, the taxpayer is impliedly giving notice of his/her intent to use such accounting.
And, this is despite the existence of IRS ruling 99-17 -- although, if you're not an attorney, it's probably not worth the risk of not formally making the election -- but I'm pretty certain I could beat the IRS on this issue.
Anyway, you're technically correct about the Schedule C issue. Nice catch.