I am a Canadian citizen studying for a PhD in the USA. From the CRA's point of view, I'm a Canadian resident; from the IRS's point of view, I'm a non-resident alien.
My investment goal is long-term growth. I opened a Roth IRA with Vanguard through my university and I am in the process opening an investment account with TD Ameritrade. I am trying to figure out how to best allocate my savings between my Roth IRA, the TD Ameritrade account, and a potential TFSA in Canada.
The most sensible first step seems to be contributing the limit to my Roth IRA. I am not sure what to do with the remainder currently sitting in my savings account. Initially, my intent was to invest it all on the US side in ETFs via TD Ameritrade. I then discovered that I have over $47,000 in accumulated contribution room in a TSFA according to "TFSA contribution room". Given the tax benefits of a TFSA, I now wonder if it would be wiser for me to invest the majority of it via a Canadian TFSA. I was initially hesitant to do so because of the conversion penalty from USD to CAD, but it looks like TD Canada Trust has an investment TFSA account that can hold and invest US dollars.
Which distribution of funds between the TD Ameritrade account and a TFSA would best achieve my investment goals (long-term growth)?