WRW

Commissions are the same - though they might add 10% GST (consumption tax that applies to pretty much everything) just to the commissions, not the whole trade amount. The platform (TWS) is the same. You can choose to log into the US, European or Asian (Hong Kong) server. Instruments available for trading (futures, equities, options, spreads) are the same except for forex - they recently suspended forex trading due to some government ruling. All correspondence is via email / TWS. Regarding margin - Reg T or Portfolio? I have Reg T - not sure if Portfolio is available for Aussies, but I think it is. I strongly suggest you contact IB Australia, not IB US.

I'm an Australian trading US equities and options with IB Australia. Got a Reg T margin account, which I think behaves the same as a US-based account. I suggest you get in touch with IB's Sydney office. As for physical location, I log into my account from all over the world and they don't care. EDIT: Just to clarify, I mean they don't care about where you trade from on any given day, but they will care about your legal place of residence. So I think you'll have to change to IB Oz when you become an Australian resident for tax purposes.