Ok, I presently live in California, but I plan on spending six months of the year in Vancouver, B.C. Is there a way I can parlay this into somehow not being a California resident? Spend a couple weeks to and from Vancouver in Seattle? Get rid of the CA license, etc. File taxes with a Canadian address and a six month visa? Do I need to have a state residency if I live out of the country for six months?
It looks subjective and not that easy. https://www.stateandlocaltax.com/california/what-makes-a-california-resident/ https://www.ftb.ca.gov/forms/2020/2020-1031-publication.pdf
You'll need to be registered in any state you do business. Residency is much more of a tax issue - FINRA and the SEC rules are very dependent on what role/products you become involved in. If you're not registered in a state,even if it's a tiny portion of your business, it can be surprisingly problematic.
Regarding US Federal (not state) taxation, familiarize yourself with the term "tax home". Turbotax has an easy to understand page about it here... https://turbotax.intuit.com/tax-tips/general/what-is-a-tax-home/L27AVL2QM
As long as your main residence is in Vancouver and you're out of California for more than 180 days you should be fine. If you have property in California, you need to ensure it cannot be construed as your permanent home. Rent it, Airbnb it during the months you're in Canada. Forward your mail, show utilities use variation when you are/are not there.
Yes you can file partial returns in US as overseas American, I think the first $96k income is tax deductible. But I am pretty sure you need a Canadian work permit to even start working there and pay Canadian tax, or any foreign country in this matter.
Trader implies full time work, taxman/woman would like to collect, can't have the cake and eat it too.
You're either a self employed trader in California or in Canada, but you can't avoid paying taxes here by declaring you're living there and vice versa.
If you want to save taxes, you should establish tax residency in Puerto Rico or Singapore, not Canada. LOL Last I heard, taxes in Canada is a lot higher than in America. As a trader, you pay 0 taxes if you can establish legal residency in Puerto Rico or Singapore, as far as I know.