Mortgage spread tracker
The 30-year mortgage rate is the 10-year Treasury yield plus a spread. The 10-year is inflation and the Fed. The spread is everything else — prepayment risk, who’s buying mortgage bonds, and how nervous they are. This page charts that second term, weekly, since 2000, so you can see how much of today’s rate is market structure rather than the Fed.
How to read it
The blue line is the spread. When it sits near the dashed average, mortgage rates are roughly where the 10-year says they should be. When it runs well above — as it did through 2022 and 2023, peaking above three points — borrowers are paying a premium that has nothing to do with inflation or the Fed, and that premium can unwind on its own.
Read the “30-yr if spread were average” stat against the current rate. That’s the whole point of this page. When the two numbers are far apart, a large slice of the mortgage rate is market structure, and it can come off without the Fed doing anything. When they are close, the spread has normalized and there is nothing left to give back — every further move has to come from the 10-year, which means from inflation. Whichever situation you’re in, the chart above says so before any commentary does.
The red line is the 10-year itself, for context. The two often move in opposite directions: in a market shock, Treasury yields fall as investors buy safety while the spread widens as they avoid mortgage bonds, and mortgage rates can end up barely moving. Reading only one line misses that.
What moves the spread
Rate volatility
When rates are jumpy, the odds that borrowers refinance early go up, and investors charge more to hold a bond that might be handed back at the worst time. Calm rate markets compress the spread.
Who’s buying mortgage bonds
The Fed bought heavily through 2021 and then stopped; banks pulled back after 2023. Fewer buyers means a wider spread. Fannie Mae and Freddie Mac’s 2026 buyback program was an attempt to narrow it from the other side.
Flight to safety
In a scare, money runs to Treasuries and away from everything else. The 10-year falls, the spread widens, and the two can cancel out for a borrower.
Servicing and guarantee costs
The fees baked into a mortgage bond — guarantee fees, servicing — are a steady floor under the spread. They move slowly and rarely make headlines.
Method
30-year fixed: Freddie Mac Primary Mortgage Market Survey, weekly, via FRED series MORTGAGE30US. 10-year: Treasury constant-maturity yield from the Federal Reserve Board, daily, via FRED series DGS10. Each weekly spread point is the Freddie observation minus the last 10-year close on or before that date. The average is the simple mean of all weekly points since January 2000. Data refreshes once a day; the latest observation date is shown above. The CSV is the full weekly series.
For what the spread means in the larger picture — where the 10-year comes from, why a Fed cut doesn’t reach your mortgage directly — read From the Fed Rate to Your Mortgage. For this month’s numbers in context, Why Mortgage Rates Are High Right Now.