Assuming Someone Else's Mortgage Is Not a Shortcut

The situation

The plan, before it broke, was about as ordinary as real estate plans get. Eun-ji, who owns a small chain of medical clinics, had one rental property already and had agreed to buy a second, a detached investment property in Port Hope listed at roughly one and a half million dollars, from a seller named Dante. Dante's existing mortgage carried an interest rate meaningfully below what new financing was likely to cost, and the agreement of purchase and sale was written on the basis that Eun-ji would assume that mortgage rather than arrange a new one - taking over Dante's loan, on its existing terms, as part of the purchase price.

Mortgage assumption is a legitimate and sometimes genuinely useful tool. Instead of the buyer arranging a brand new mortgage, which involves fresh underwriting, new legal fees, and current market rates, the buyer steps into the seller's existing loan, subject to the lender agreeing to the substitution. Done properly, it can save money and time. It is also, by its nature, conditional on something the buyer does not fully control: the lender's willingness to accept the new borrower in place of the old one, based on a review of that new borrower's finances - their covenant, in lending terms.

Eun-ji's business partner Jomar, who owns a multi-unit franchise operation and had helped her look over the numbers informally, was confident the assumption would be a formality. Eun-ji's income from the clinics was substantial, and on paper she looked like an easy approval. What that view did not weigh properly was that Eun-ji also carried significant existing debt tied to the clinics themselves - equipment financing, a line of credit against the business, and the mortgage on her first rental property - all of which a lender reviewing her covenant for a new assumption would see in full, not just the income side of the picture.

The closing date was set forty-five days out, tight but workable if the assumption went through cleanly. Eun-ji had budgeted for the deal on the assumption that it would close on the existing mortgage's below-market rate, and had not seriously priced out what the property would cost her with a new mortgage at current rates instead. That gap, more than anything else, is what turned an ordinary plan into a genuine problem once the lender's answer came back.

What was actually at stake

When the lender's covenant review came back roughly three weeks before closing, the answer was a refusal, not a request for more information. The lender's underwriters had looked at Eun-ji's total debt obligations across the clinics and her existing rental mortgage and concluded her overall debt load, relative to her income, did not meet the threshold they required to accept her as a substitute borrower on Dante's existing mortgage. The refusal was final as far as that specific mortgage was concerned; the lender was not interested in negotiating around it for an assumption, though a fresh application under different underwriting criteria remained possible.

What was actually at stake was larger than the interest rate difference. The purchase agreement had a financing condition tied specifically to the assumption being approved, and that condition's deadline was approaching fast. If it simply expired unsatisfied and unwaived, the agreement would be at an end and Eun-ji's deposit - a substantial sum, put down in good faith on a deal both sides had expected to close - would come back to her in full. The real danger sat one step further along: if Eun-ji waived the condition to keep the deal alive and then could not actually close because replacement financing was not ready in time, that would be a default of her own making, and Dante could then look to the deposit as compensation for the failed transaction. Losing the deposit that way - not because the condition failed, but because of an unwise waiver followed by an inability to close - was a real possibility, not a hypothetical one.

The second thing at stake was time. Arranging entirely new financing, at current market rates, with a different lender or the same one under standard underwriting, is not something that happens in days. It requires a fresh application, an appraisal, income verification, and underwriting review, all of which take real time even when a borrower is well qualified. With three weeks left before the scheduled closing, there was a genuine risk that even a successful new mortgage application would not be ready in time, which would put Eun-ji in default on the purchase agreement regardless of whether financing eventually came through.

The third thing at stake, and the one that shaped how the file actually played out, was Eun-ji's own instinct once the refusal came in. Facing the prospect of losing both the deal and the deposit, she wanted to move fast and cheap - waive the financing condition immediately to keep the deal alive on paper, on the theory that financing would surely come together somehow, and avoid the cost of engaging a mortgage broker properly. That instinct, understandable under pressure, would have removed her only real protection at exactly the moment she needed it most.

What we did

1. Reviewed the financing condition's exact wording before anyone made a decision under pressure, confirming what deadline actually applied, what would satisfy it, and what the consequences of an unwaived, unfulfilled condition would be for both the deposit and the deal, so Eun-ji was working from facts rather than fear. The condition, as written, required financing satisfactory to Eun-ji, in her sole discretion, which mattered enormously once the assumption fell through and a different kind of financing had to be found instead.
2. Advised against waiving the financing condition immediately, despite Eun-ji's preference for a fast resolution, because waiving it without replacement financing actually in place would have converted a conditional deal she could walk away from into a firm obligation she might not be able to complete - trading a contained risk for an open-ended one, with the deposit as the price of guessing wrong.
3. Set out the realistic timeline for both paths in writing - waiving now versus arranging real financing first - so Eun-ji could see plainly that the faster-looking option was also the riskier one, rather than taking our advice against it on faith alone. Laid out side by side, the numbers made clear that a few days saved by waiving early were not worth the possibility of an unconditional obligation with no financing behind it.
4. Engaged a mortgage broker with experience in investment property financing the same week the assumption was refused, rather than relying on Jomar's informal read of the numbers, to get a realistic, current picture of what new financing she could actually qualify for and how quickly. The broker's assessment, grounded in an actual application rather than an estimate, became the evidence we needed to negotiate credibly with Dante's side about extending the deadline.
5. Negotiated a short extension to the financing condition deadline with Dante's lawyer, presenting Eun-ji's application for replacement financing as evidence of genuine progress rather than delay, which gave the new mortgage application enough runway to actually close before the extended date. Dante had his own reasons to want this deal to close rather than restart with a new buyer, which made the extension an easier conversation than it might otherwise have been.
6. Reviewed the replacement mortgage's terms closely once an offer came through, confirming the rate, the amortization, and the closing costs against what Eun-ji could actually carry alongside her existing obligations, rather than accepting the first approval simply because time was short. We flagged a prepayment penalty clause buried in the commitment letter that would have cost her materially if she refinanced again within the first three years.
7. Recalculated Eun-ji's closing costs and ongoing carrying costs under the new financing and walked her through the real gap between what she had originally budgeted and what the deal would now cost her monthly, so she was closing with accurate numbers rather than the ones from her original plan. Seeing the revised numbers in writing, before closing rather than after, let her adjust her rental pricing expectations instead of discovering the shortfall later.
8. Coordinated the closing itself around the new mortgage instead of the assumption, working with the lender's solicitor on the standard requirements for a fresh purchase financing rather than the assumption documentation that was no longer relevant, to keep the revised closing date achievable. That meant redoing title and off-title searches on a compressed timeline, since the assumption route would have relied on searches the seller's own lender had already completed.
9. Confirmed the deposit's status with Dante's lawyer once the extended condition was satisfied, making sure it was formally credited toward closing rather than left in an ambiguous position that could have become its own dispute if anything else had gone wrong before the revised date. A deposit sitting in an unclear state, even briefly, is exactly the kind of loose end that turns into a disagreement once a deal is under real time pressure.

The outcome

The deal closed, roughly ten days later than originally scheduled, on new financing rather than the assumed mortgage Eun-ji had planned around. That is the honest shape of the outcome: it was not a clean win. Eun-ji ended up with a mortgage at a materially higher rate than Dante's original loan, higher monthly carrying costs on the rental than she had budgeted for, and the added expense of a mortgage broker and rushed underwriting fees she had hoped to avoid entirely.

What did not happen was the worse outcome that was genuinely on the table three weeks before closing: losing both the property and a substantial deposit by waiving the financing condition to keep the deal alive and then being unable to close on time. That was the real risk once the assumption was refused, and it was avoided by not waiving the condition prematurely and by treating the replacement financing search as urgent from the first week rather than the last.

Eun-ji has said plainly, looking back, that her instinct to move fast and cheap in the first days after the refusal would have made things considerably worse, not better - waiving the condition to keep the deal looking alive on paper would have removed her only leverage exactly when she needed it. The property closed, the rental is generating income, and the higher borrowing cost is a real, ongoing expense she is carrying because the original assumption fell through - a contained loss rather than an avoided one, and a reminder that a mortgage assumption is never guaranteed until the lender's own review says so.

Jomar, who had pushed the assumption as a safe formality at the outset, later said the episode changed how he looks at every deal he brings to Eun-ji since - not as a reason to avoid assumptions altogether, but as a reason to treat the lender's covenant review as the real decision point, not a rubber stamp on a plan already assumed to be settled.

What you can learn from this