Private mortgage lender cross-border tax: US investors and US-secured loans

A MIC payment to a US investor is withheld as a dividend

The tax mechanic that makes a MIC attractive to a resident investor — its payouts are treated as interest income rather than dividend income in their hands — does not change what the payment legally is at the corporate level: a dividend on shares. When that dividend is paid to a non-resident, including a US-resident investor, Canada applies Part XIII withholding tax on dividends, at a default statutory rate of 25%, generally reduced under the Canada-US tax treaty for a portfolio holding once the investor files the paperwork confirming their treaty residency. The exact treaty rate and the documentation required can shift with treaty updates, so we confirm the current rate before assuming the reduced figure automatically applies.

This distinction is easy to miss precisely because the domestic marketing of a MIC leans so heavily on the interest-like character of its payouts. A fund manager who assumes a US investor's distribution is simply "interest, no different than what a Canadian shareholder gets" can under-withhold without realizing it — the withholding obligation sits with the fund, not the investor, and a shortfall discovered later becomes the fund's problem to fix.

NR4 slips and NR301 declarations replace the domestic paperwork

A US-resident shareholder of a MIC receives an NR4 slip rather than the T5 a Canadian shareholder gets, and the reduced treaty withholding rate is only available once the investor has filed an NR301 declaration confirming their US residency and treaty eligibility with the fund. Without that form on file, the fund is expected to withhold at the full 25% statutory rate regardless of where the investor actually lives — a paperwork gap that costs the investor real money and is entirely preventable with an intake process that collects the form before the first distribution goes out. We build that collection step into onboarding for any fund with, or actively seeking, US investors, rather than chasing the form down after withholding has already been remitted at the higher rate.

Lending against US property raises the mirror-image question

If a Canadian private lender or MIC finances a mortgage secured by property in the United States, the interest the US borrower pays back may itself be subject to US withholding tax on payments to a foreign lender, unless it qualifies for the US portfolio interest exemption — a US domestic-law relief that can eliminate withholding on certain interest paid to foreign lenders, subject to conditions around the lender's relationship to the borrower and the type of debt involved. Where the exemption does not clearly apply, treaty relief may reduce the rate instead, but neither outcome is automatic. This is a review to run on the specific loan structure before funding it, not an assumption to make because the loan is styled the same as a domestic Canadian mortgage.

The exemption generally depends on the lender not holding a significant ownership stake in the borrower and the debt not being tied to certain equity-linked terms — conditions that matter more than they first appear once a private lender starts structuring creative terms into a US-secured deal. Confirming the exemption applies, or planning around the withholding if it does not, changes the actual yield on the loan and belongs in the underwriting decision, not an afterthought once funds have already moved.

Which direction the money moves changes the exposure

Where this fits with the rest of the file

Every fund taking on US investors or US-secured loans should treat this review as ongoing, not a one-time check at launch — new investors and new loan structures both reset the analysis, and a change in either the treaty or domestic legislation on either side of the border can shift the numbers without anyone at the fund noticing until a return is filed. The domestic tax mechanics this sits alongside are on our lender tax services page, and our full Canada-US practice is described on our cross-border tax services page.

Source: CRA — Non-resident withholding tax.