That is correct. As a MTM trader expenses go on Schedule C. Your MTM (trading) income/loss goes to Form 4797 and from there to line 4 on schedule 1. You have to decide if the HO deduction is worth the increased risk of audit. Another potential issue is if your schedule C loss, Trading profits and HO deuction routinely result in a net loss. the IRS could deny you the deduction on the basis that the activity was not enter into for profit. Code section 183
