[mrkajz44]

The issue with "sourced" income depends on the type of income.

Dividend income is typically sourced based on where the dividends were paid from. Therefore, if the company is US based, then the dividends are considered US source.

Interest income is different and usually based on your residency, rather than where the interest was paid. So if you were a resident in the US in the entire year, all interest income should be sourced to the US.

The tax treaty have have changed since I did US personal taxes in 2009 though, but that's what I remember.

And yes, the US tax system is way more complicated, both personal and corporate. Just compare the size of the Canadian act and regulations (one book) and the US code and regulations (typcially 6-8 books).