Cap Rates at 7.3%, Mortgages at 6.71%: Recalculate the Spread Before the Fed Cuts

Half the acquisition emails in your inbox this month are built on the same assumption: the Fed cuts in September, mortgage rates follow, and the deals that do not pencil today will pencil by Q4.

Here is the uncomfortable part. The Fed does not set your mortgage rate. And even if the 30-year fell the full 25 basis points, the cap rate vs mortgage rate spread on a typical single-family acquisition would still be upside down.

National SFR cap rates sit at 7.3%. The 30-year fixed just printed 6.71%. That looks like 59 basis points of room. Run the amortization and the room disappears.

Why the Fed Funds Rate Is Not Your Mortgage Rate

The federal funds rate is an overnight bank lending rate. Your 30-year mortgage is priced off long-term bond markets, primarily the 10-year Treasury and mortgage-backed securities spreads.

Those two things move together sometimes and apart often. As Bankrate's explainer on the Fed and mortgage rates lays out, the relationship runs through expectations rather than mechanics. By the time a cut is announced, the bond market has usually priced it in weeks earlier.

The recent history is instructive. Mortgage rates fell ahead of the Fed's September 2025 cut, then rose after it. Investors who timed acquisitions to the announcement bought at worse pricing than investors who did not wait.

None of this means rates will not come down. It means the announcement is not the event, and a cut is not a business plan.

The Spread Today: A 7.3% Cap Rate Against a 6.71% Mortgage Rate

Start with where both numbers actually are.

Freddie Mac put the 30-year fixed at 6.71% on September 3, up from 6.66% the prior week and 6.50% a year earlier. That is roughly an eleven-month high.

On the asset side, SFR cap rates reached 7.3%, a climb of about 194 basis points since 2021, with average occupancy at 94.0%, according to CRE Daily's reporting on Arbor research.

Cap rates rose for a reason worth naming. The climb came from slower home price growth and normalizing rents, not from a sudden improvement in asset quality. You are being paid more yield because the growth assumption underneath it got smaller. We unpacked where that repricing landed regionally in our look at Midwest SFR cap rates.

Two more things to hold onto. The 6.71% figure is the owner-occupied benchmark, and investor debt typically prices above it. And a 7.3% national average flattens enormous market-level variation.

The Leverage Math, Shown

Take the median small-investor purchase price: $330,000, per Realtor.com data reported by HousingWire. Apply the 7.3% cap rate. Finance it conventionally.

• Purchase price: $330,000
• NOI at a 7.3% cap: $24,090 per year
• Down payment at 25%: $82,500
• Loan amount: $247,500 at 6.71%, 30-year amortizing
• Annual debt service: about $19,185
• Cash flow before capex and vacancy: about $4,905

That looks survivable until you compute the number that actually governs leverage.

Your comparison point is not the interest rate. It is the debt constant: annual debt service divided by loan amount. Amortization is part of your payment, so it belongs in the comparison.

$19,185 divided by $247,500 is a debt constant of 7.75%.

Against a 7.3% cap rate, that is negative leverage. Every borrowed dollar costs 45 basis points more than the asset yields on it. Debt is not amplifying your return. It is diluting it. Cash-on-cash lands near 5.9% on the down payment, before closing costs, which is well below the 7.3% you would earn unlevered.

At investor pricing closer to 7.25%, the constant climbs to about 8.2% and the gap widens further.

Joe's read: Everybody quotes the interest rate. The debt constant is the one that decides whether leverage is working for you or quietly working against you. If the constant is above your cap rate, you are paying for the privilege of borrowing.

What a 25-Basis-Point Cut Actually Does

Run the optimistic case. Assume the Fed cuts and the 30-year passes the full 25 basis points through to 6.46%, which is more generous than history suggests.

On the same $247,500 loan, annual debt service falls from about $19,185 to about $18,694. That is a saving of roughly $491 a year, or about $41 a month.

The debt constant drops from 7.75% to about 7.55%. Still above the 7.3% cap rate. Still negative leverage.

Forty-one dollars a month is not nothing. It is also not the reason a deal works or fails, and it is a poor basis for holding capital on the sidelines through a quarter. A deal that needs a rate cut to clear your hurdle is a deal that is priced wrong for you today.

Three Levers That Widen the Spread When Rates Will Not

If the debt side is stuck, the return has to come from somewhere you control.

1. Entry basis. Buying the same NOI for less money raises your cap rate directly. On the $24,090 NOI above, paying $310,000 instead of $330,000 moves your going-in cap from 7.3% to about 7.8%, which clears the 7.75% debt constant and tips leverage back to neutral-to-positive. Twenty thousand dollars of basis is worth more than a rate cut. Basis is also the fastest lever, and it is almost entirely a sourcing question.

2. Occupancy from day one. The national average to lease an SFR runs about 32 days. On a $330,000 asset, that vacancy window plus a turn costs more than a full year of current rent growth. Acquiring an already-occupied asset removes the line item instead of budgeting for it. We ran those numbers in our piece on building a zero-vacancy SFR portfolio.

3. Leverage discipline. When the constant exceeds the cap rate, more debt makes the return worse. Running 25% down instead of 20%, or using shorter amortization deliberately, is a defensible choice in a negative-leverage environment rather than a failure of ambition.

How to Reunderwrite for Q4

1. Replace interest rate with debt constant in every model you run. Compare it to the going-in cap rate before anything else.
2. Underwrite at today's quoted rate. No forward-rate assumption, no cut priced in.
3. Set a basis threshold, not a price target. Decide what cap rate makes leverage work, then let that dictate the offer.
4. Stress the spread. Check what happens if rates rise 50 basis points rather than only modeling the downside.
5. Price occupancy explicitly. Give a tenant-in-place acquisition credit for the lease-up and turn cost it removes.

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The Practical Takeaway

A 7.3% cap rate against a 6.71% mortgage rate does not describe a 59-basis-point cushion. Once amortization enters the calculation, it describes negative leverage, and a September cut does not resolve it.

The investors who do well in this stretch will not be the ones who called the Fed correctly. They will be the ones who bought at a basis that did not require the Fed to be right.

Figures above are illustrative and use national averages. Cap rates, rents and loan pricing vary substantially by market and borrower.