How Mortgage Rates Are Set: The 10 Year Treasury Rule Explained

Every week somebody asks me the same thing. “Moe, the Fed raised rates, so why did my mortgage rate go down?” Or the opposite. “The Fed didn’t do anything, so why did my rate just jump a quarter point?” If that’s ever confused you, this is the page for you. Once you understand the one equation behind your mortgage rate, the headlines stop being scary and start making sense.

I’m going to keep this simple. I was a financial advisor, I’ve taught finance for years, and I own real estate with mortgages on it, so I watch this stuff like a hawk. Here’s how mortgage rates are actually set, and how you can estimate where they’re going yourself.

What the Fed controls and what it doesn’t

The Federal Reserve sets one number: the federal funds rate. That’s the overnight rate banks charge each other. It moves credit cards, auto loans, home equity lines and what your savings account pays. When the Fed hikes, those costs go up fast.

It does not set the 30 year mortgage. A 30 year loan lasts, well, 30 years, but most get paid off or refinanced well before that. So lenders price them off a longer term number. That number is the 10 year Treasury yield.

That’s why you’ll see strange things happen. In September 2026 the Fed raised its target range to 3.75% to 4.00%, its first hike since July 2023, and mortgage rates actually dipped the next day. Traders had already priced the hike in. By the time the Fed acts, the bond market has usually moved already. Markets price the future, not today.

The one equation behind your mortgage rate

Here it is. Write it down.

30 year mortgage rate = 10 year Treasury yield + the spread

On September 24, 2026, the 10 year was 5.17% and the spread was 1.85%. Add them up and you get 7.02%. Freddie Mac’s survey that week said 7.03%. One basis point off. That is how tight this relationship is.

The quick version I always give people: take the 10 year and add about 2%. If the 10 year is at 5%, mortgages are going to be around 7%. If it’s at 4%, think around 6%. You can check the 10 year on any finance site in five seconds, so you’ll always have a rough idea where rates are before the weekly survey comes out.

What the spread is and why it moves

The spread is what lenders and mortgage bond investors add on top of Treasuries. They want to get paid for a few things a Treasury doesn’t have: the chance you refinance early, the chance you default, and the cost of making and servicing the loan.

Its long run average is about 170 to 180 basis points, or 1.7% to 1.8%. A few things push it wider:

• Bond market volatility. When rates are swinging around, investors demand more to hold mortgage bonds.
• The Fed shrinking its mortgage bonds. The Fed still holds about $1.91 trillion of them and is letting $15 to $18 billion a month roll off. Less of a big buyer means a wider spread.
• Stress in the system. In 2023 the spread went above 300 basis points. That alone added more than a full point to mortgage rates with no help from Treasuries.

Keep this in mind. A wider spread can push you to 8% even if the 10 year doesn’t move at all. And if the spread squeezes back toward normal, rates can drop a little even while Treasuries sit still.

What moves the 10 year Treasury

If the 10 year drives most of your rate, the next question is what drives the 10 year. Four big things:

• Inflation. Bond investors want to be paid more than inflation. When inflation runs hot, yields climb. The Fed’s preferred gauge, core PCE, was running around 3.4% in 2026 against a 2% target.
• Where the Fed is heading. Not what it did today, but what traders think it’ll do over the next few years.
• Government borrowing. The more Treasuries the government has to sell, the more yield it may have to offer to find buyers. The deficit is the wild card nobody can model.
• The rest of the world. Yields move together globally. In September 2026, German 10 year yields hit a 17 year high and Japanese 10 year yields hit their highest since 1996, at the same time ours hit a 19 year high.

Strong jobs and strong spending usually push yields up too. That sounds backwards, but a hot economy means more inflation risk and fewer rate cuts.

Why you see four different “current” rates

You’ll see one number on the news and a different one from your lender. They are not lying. They are measuring different things.

• Freddie Mac’s weekly survey is the headline number. It is an average of loans offered from the prior Thursday through Wednesday, so it is always a few days stale.
• Mortgage News Daily reads lender rate sheets every day, so it catches big moves first. On September 24, 2026 it hit 7.45% while the Freddie Mac headline still said 7.03%.
• Bankrate and lender sites post their own averages and quotes, which can include points or assume a great credit score.

If the bond market moved hard this week, trust the daily number over the weekly one.

What decides the rate you personally get

The equation tells you where the market is. Your own quote can land above or below that, depending on:

• Credit score. Better scores get better pricing. This is one of the biggest levers you control.
• Down payment. Putting down 20% or more avoids private mortgage insurance and usually improves your rate.
• Loan type and term. A 15 year loan is usually well under a 30 year. On October 1, 2026, Freddie Mac had the 15 year at 6.60% versus 7.28% for the 30 year. FHA and VA loans price differently again.
• Points. You can pay money upfront to buy the rate down. It is not free money. You are paying for it now instead of later.
• Property type. Investment properties and second homes usually cost more than a primary home. I have a 6.99% loan on one of my investment properties, which tells you how that goes.

Those builder ads for a 3.9% mortgage when the market is near 7%? Somebody paid for that buydown, and it’s usually baked into the price of the house. Ask what the price would be at the market rate. You might do better taking the market rate and asking for that money off the price.

Mortgage rates through history

Freddie Mac has tracked the 30 year fixed since April 1971. The average by decade puts today in perspective:

• 1980s: about 12.7%
• 1990s: about 8.1%
• 2000s: about 6.3%
• 2010s: about 4.1%
• 2020s so far: about 5.4%

The all time high was 18.63% in October 1981. The all time low was 2.65% in January 2021. The 55 year average is about 7.7%. So a 7% rate is not crazy by history. What’s different now is that home prices are so high compared to income. Rates in the 80s and 90s were in double digits, but homes were dirt cheap next to what people earned. That’s the brick wall in front of a lot of young buyers today, and it is not their fault.

How to estimate where rates go next

You can work backwards from the rate you want. Assuming a spread near 1.85%:

• A 6% mortgage needs the 10 year around 4.15%.
• A 5% mortgage needs the 10 year around 3.15%. That is recession territory.
• An 8% mortgage needs either the 10 year above 6% or the spread blowing back out to 2023 levels. The spread path is the faster one.

Every 25 basis points off the 10 year takes roughly 25 basis points off your mortgage. So when you hear the 10 year dropped a quarter point on a weak jobs report, you already know what that means for you. If you want my full year by year numbers, I laid them out in my 10 year mortgage rate forecast.

When refinancing makes sense

The old rule I was taught: if you can drop your rate by half a point and you’re going to stay in the home, start shopping. Personally, I like to wait for a full point. At half a point I start looking. A full point is a no brainer.

Don’t forget closing costs. Divide what the refinance costs by what you save each month. That is how many months it takes to break even. If you’ll move before then, it is not worth it.

And if you’ve got a mortgage in the 3s, you probably already know the answer. I’ve got one around 3.2% and I’m staying put. Nearly 79% of homeowners with a mortgage have a rate under 6%. That’s a big reason so few homes are for sale.

Common questions

Does the Fed set mortgage rates?
No. The Fed sets the overnight rate. Mortgage rates follow the 10 year Treasury yield plus a spread.

Why did mortgage rates go down after the Fed raised rates?
Because the bond market had already priced the hike in. Sometimes bond investors like seeing the Fed fight inflation, which can pull longer term yields down.

What’s a normal spread between the 10 year and mortgage rates?
About 1.7% to 1.8% over the long run. It has ranged from about 1.5% to above 3%.

How often do mortgage rates change?
Every day. Lenders reprice off the bond market, sometimes more than once a day. Freddie Mac’s survey only updates on Thursdays.

Will mortgage rates go back to 3%?
That would take the 10 year near 1%, which only happened during a crisis. I wouldn’t plan your life around it.

Keep reading on Stock Moe

• My 10 Year Mortgage Rate Forecast: 6.6% in 2027, 6.1% by 2031
• Mortgage Rates Hit 7.50%: 54 Cities Falling, No Crash Yet
• Mortgage Rates Hit 7.45%: What Changed and What It Costs You
• The Fed Raised Rates, So Why Did Mortgage Rates Drop?
• Housing Market Update: 7% Mortgages and Record Seller Concessions

If you want my notes on rates and the market every week, grab the free Stock Moe Sunday Letter.

Sources

• Freddie Mac Primary Mortgage Market Survey, October 1, 2026, September 24, 2026, and the historical series since April 1971
• US Treasury daily yield curve, September and October 2026
• Federal Reserve FOMC statement and Summary of Economic Projections, September 16, 2026
• Federal Reserve balance sheet data on mortgage backed securities holdings
• Mortgage News Daily 30 year rate index, September 2026
• Stock Moe calculations from the sources above

I am not a financial advisor and nothing in this article is financial advice. Everything here is my own opinion, for educational and entertainment purposes only. Do your own research and talk to a licensed professional before you make any financial decision.