As of decades ago, if the car is owned by an incorporated business you can expense the whole car. Otherwise you can only expense business purpose mileage. If it is a home based business it would be a good idea to have a second personal car. I could be wrong.
Without knowing where you are and what type of entity you're trading through nobody can advise you with any certainty. Ask your accountant.
Haven’t done it yet, but my understanding is that the easiest way is to lease the car, which would be 100% deductible including insurance. You must not use the car for your personal use, but as long as you don’t abuse it, I doubt it will be an issue.
I'm in California and looking at TTS / S-Corp next year. Trying to see if I can offset some of my car lease payments on a 2nd "company" car that I'm shopping for. Does IRS care if it's a luxury car provided the expenses I'm looking to deduct is reasonable? I'm happy if I can offset part of the lease payments as a "perk" from my trading gains. Thanks.
"The deduction is allowed only for that part of the expenses that is attributable to business." As in needed to operate business. Traders Tax Survival Guide.
Possible to expense car payments as home based trader? Possible, sure. There are always "exceptions" to the tax laws. For most however, in practice as a "home-based trader", there are not many instances where a vehicle is REQUIRED for the business operation. Now then, if you taking on clients, running an advisory service, or promoting other products and services beyond claiming to be a "home-based trader", a vehicle may be necessary to conduct a for-profit business. All that said, if the business creates an "accountable plan", certain vehicle (and other) expenses MAY be eligible for reimbursement, without taxation to you, and used as an expense by the company.