it's optional for an active trader to make the mark-to-mark election - 475(f) election. if a trader wants to make this election it must be done by the original due date of the return (either by filing the election with the return or attached to a timely filed extension) for the year before the year the election is to become effective.
Traders report their business expenses on Schedule C (Form 1040 or 1040-SR), Profit or Loss from Business (Sole Proprietorship). Commissions and other costs of acquiring or disposing of securities aren't deductible but must be used to figure gain or loss upon disposition of the securities.
without the election, the wash sale rules apply and the gains /losses are reported on schedule D. with the election, the wash sale rules don't apply and the gains/losses are reported on form 4797 part II
