US non resident tax implications for Canadians

[bernard]

Hello again Steven. I was travelling and just now reviewing your post - thank you. What if I stayed in the US longer than 183 days in a calander/tax year (say 9 months in all) but was not earning in the US and not renting out the apartment so no income from that and still officially non resident of Canada would that length of time potentially red flag me?

[Steven]

If you're a visitor and you have closer ties to another country, then you're not resident in the US for tax purposes, simple as that. There's frankly no way of the IRS determining you are there because you have no SSN and you're not required to file a tax return so as far as the IRS is concerned you don't exist. The whole purpose of the W-8BEN form is stop people from reporting to the IRS because you're claiming a tax treaty benefit on it so they don't have to perform any withholding.

Where you're more likely to get into trouble is with CBP, because if you're spending lengthy periods in the US they may consider you to not be a visitor.