You find a triplex listed at $255,000. The seller says, "I'll carry the note myself, 7 percent, five-year balloon, no bank needed." Your gut reaction is probably relief. No appraisal fight, no underwriter asking for three years of tax returns, no 45-day close. But that relief is exactly where most buyers stop thinking and start signing.

Seller financing doesn't just remove a lender from the transaction. It removes the entire underwriting framework a bank would have forced you through, and hands you the job of doing it yourself, correctly, with your own money on the line.

The bank's checks disappear, but the risks don't

When a bank finances a rental, it runs a DSCR test, orders an appraisal, and checks title for liens. Those steps are annoying, but they catch real problems before you close.

With seller financing, none of that happens automatically. The seller isn't going to flag that the property is overpriced for the market, and there's no appraiser forcing a reality check on value. You have to build that discipline yourself, or you inherit whatever risk the seller was happy to offload.

This matters most on price. Sellers who carry paper often ask a premium above market value because they're offering financing nobody else will. A $255,000 asking price might really be worth $230,000 on the open market. If you don't run your own comps and rent analysis independently of the seller's terms, you can end up overpaying by 10 percent just because the rate looked friendly.

Price and rate are the same lever, not two

Sellers who carry notes almost always trade price for rate, or rate for price. A seller who wants full asking price will often accept a lower interest rate to get there. One who's flexible on price will usually want a higher rate to compensate.

If you underwrite the price and the rate as separate line items, you'll miss this. Run both scenarios: full price at a low rate, and a discounted price at a higher rate, and compare total cash flow and total cost over your hold period. Often they land close to the same effective deal, and the one that looks better on a rent roll spreadsheet isn't always the one that's actually cheaper.

The balloon is the deal, not a footnote

Most seller-financed rentals aren't fully amortizing 30-year loans. They're interest-only notes with a balloon payment in three, five, or seven years. That balloon is the single biggest underwriting variable, and it's the one investors most often gloss over because it's not due this year.

Here's the problem: a balloon payment is a bet on future refinance conditions you can't fully control. Rates might be higher in five years. Your property might not appraise where you need it to. If either happens, you're forced into a fire sale or a much worse loan than the one you started with.

The fix is to underwrite the refinance now, using conservative assumptions, not just the purchase.

Worked example: the triplex with the wraparound

Back to that $255,000 triplex. You put $51,000 down and the seller carries $204,000 at 7 percent, interest-only, with a balloon due in five years. The seller still owes $140,000 on their own mortgage at 4 percent, which stays in place underneath your note, a wraparound structure.

Gross rent across three units is $3,300 a month, or $39,600 a year. After running 35 percent for expenses (taxes, insurance, maintenance, vacancy, management), your NOI is $25,740 a year.

Your interest-only payment on the $204,000 note is $14,280 a year. That leaves $11,460 in annual cash flow, an 22.5 percent cash-on-cash return on your $51,000 down payment. That number alone would make most investors sign immediately.

But check the wrap. Your monthly payment to the seller is $1,190. The seller's own mortgage payment is roughly $670 a month. That gap of $520 is the seller's profit margin, and it's also the reason this deal exists at all, the seller is getting paid to hold paper they'd otherwise have to sell outright.

The real test is the balloon. In five years, you owe $204,000 in one payment. To refinance conventionally, a bank will want your NOI to support the new loan at a reasonable DSCR. At a 7 percent amortized rate over 30 years, that $204,000 loan costs roughly $16,300 a year in debt service. Against your $25,740 NOI, that's a 1.58 DSCR, comfortably financeable, assuming rents hold and expenses don't spike.

That DSCR check is the number that actually tells you whether this deal survives past year five. The 22.5 percent cash-on-cash number is nice, but it's not the number that determines whether you keep the property or lose it in a refinance crunch.

One more risk to model: due-on-sale clauses. If the seller's underlying lender discovers the wraparound sale, they can technically call the entire $140,000 balance due immediately. It rarely happens in practice, but "rarely" isn't the same as "never," and it's a line item that belongs in your risk assessment, not an afterthought you find out about after closing.

Model the whole structure before you sign anything

Seller-financed deals reward buyers who underwrite the balloon date, the wrap risk, and the refinance DSCR just as carefully as the monthly cash flow. Most investors run the easy numbers and skip the hard ones because the easy numbers already feel good enough to sign.

Cylier's AI investment reports run both. When a deal includes seller financing terms, the report models the balloon payoff, tests refinance feasibility at conservative future rates, and flags wraparound and due-on-sale exposure alongside the standard cash flow and cap rate numbers. You get the full structure in your inbox before you're five years deep in a note that looked great on day one.