Posted: Sun Feb 24, 2008 10:26 pm-
Residency for tax purposes in Canada is 90 days. However, there have been a multitude of court cases about it and the CRA can also consider you resident if you have a substantial presence in Canada, i.e. driver's licence, premises, that sort of thing.
If you plan on being in the US for multiple years you're probably better off severing ties with Canada for tax purposes, there is a whole section on the CRA website about non-residency. Look at Form NR73.
If you don't want to do it or it's impractical, you can claim a closer association to Canada via IRS Form 8840 when you file your 1040NR. This is the better option if you plan on moving back anytime soon. If you leave Canada permanently for tax purposes, you become subject to the capital gains tax if you resided in Canada for more than 5 years before you left, you need to consider that one also.
My personal feeling on this one is that you need to be very careful about it if you are there on a work permit, because if you lose your job, you will have to move back to Canada presumably. That will create an awfully sticky tax situation, so plan ahead and figure out exactly what your future plans are.
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Steve.