US citizens and green card holders are taxed on worldwide income regardless of where they live.

US Substantial Presence Test: You're a US tax resident if you spent 31+ days in the US in the current year AND 183+ days over 3 years (weighted formula).

Canada: You're a Canadian tax resident if Canada is where you maintain significant residential ties.

Treaty tie-breaker: permanent home → center of vital interests → habitual abode → citizenship.

FBAR (FinCEN 114): If aggregate value of foreign accounts exceeds $10,000 at any point, you must file. Penalties: up to $16,536 per non-willful violation.

FATCA (Form 8938): Report foreign assets exceeding:

• US residents: $50,000 year-end / $75,000 any time (single)
• Living abroad: $200,000 year-end / $300,000 any time (single)

Foreign Tax Credit (Form 1116): Dollar-for-dollar credit for taxes paid to Canada. Can carry back 1 year or forward 10.

Foreign Earned Income Exclusion (Form 2555): Exclude up to $130,000 (2025) of foreign earned income.

You can't use both on the same income. FTC is usually better for Canadian-source income.

RRSP: The US-Canada treaty recognizes RRSPs. You can elect to defer US tax on RRSP income.

TFSA: The US does not recognize TFSAs. All income earned inside a TFSA is taxable for US purposes. Consider it a regular taxable account.

Closer Connection Exception (Form 8840): If you have a closer connection to Canada, file this annually to avoid US tax residency despite meeting the presence test.

Prevents double Social Security taxation. You generally pay SS/CPP taxes only to the country where you work. Get a Certificate of Coverage to prove exemption.

If you're a "covered expatriate" (net worth ≥ $2M, avg net income tax ≥ ~$206,000, or can't certify compliance), gain above the $890,000 exclusion is taxed immediately.