What actually moves mortgage rates?
A 30-year mortgage rate is the 10-year Treasury yield (the bond market’s base price of long-term money) plus a total spread that has historically run roughly 1.7–2.0 percentage points — and wider in stressed markets like 2022–2023. That spread is itself two stacked pieces: the premium investors demand to hold mortgage-backed securities instead of Treasuries, and the primary–secondary spread that covers guarantee fees, servicing costs, and lender margins. The Fed’s short-term rate influences all of this only indirectly — which is why mortgage rates sometimes rise on the day of a Fed cut. You cannot shop the market pieces; the lender-margin slice inside that spread is the part competition reaches, and it is why identical borrowers get different quotes on the same day.
Last reviewed 2026-08-24
| Key number | Value | Source |
|---|---|---|
| Total spread: 30-year mortgage rate vs 10-year Treasury | historically roughly 1.7–2.0 percentage points; well wider in 2022–2023 | Federal Reserve Bank of New York (primary–secondary spread research) |
Layer one: the 10-year Treasury
A 30-year mortgage is long-term lending, so its price keys off long-term bonds — the 10-year Treasury is the standard reference because most mortgages end (by sale or refinance) long before year 30. When inflation expectations rise or the economy runs hot, yields climb and mortgage rates follow; when investors flee to safety, yields fall and mortgages cheapen. This layer moves daily on economic data, and a single inflation report can move it more in an afternoon than any lender’s pricing decision.
Layer two: the spread — two pieces nobody separates
The gap between the quoted 30-year rate and the 10-year Treasury — historically about 1.7 to 2.0 percentage points in total — is really two components stacked together. The first is the premium investors demand to hold mortgage-backed securities instead of Treasuries: borrowers refinance exactly when investors least want them to, and MBS carry more volatility. The second is the primary–secondary spread between what investors accept and what borrowers are quoted, which pays for guarantee fees, servicing, origination costs, and lender profit. In stressed markets like 2022–2023 the total spread widened well beyond its historical range, which is how mortgage rates climbed even on days Treasury yields improved — falling-yield headlines can be true while your quote refuses to budge.
Layer three: the lender-margin slice — the only part you can shop
Inside that primary–secondary spread sits each lender’s own markup covering operations, risk, and profit. This slice is where a bank differs from a credit union differs from a wholesale lender priced through a broker, and it is the entire reason comparison shopping works: the market components of the spread charge everyone the same, but margins vary by institution, by channel, and even by how busy a lender happens to be. Freddie Mac’s research finding that shoppers save roughly $600–$1,200 a year is a measurement of margin dispersion. How many lenders to quote
Why the Fed is not your mortgage rate
The Fed sets an overnight rate; mortgages price off long-term expectations. Markets move on what they expect the Fed to do long before it does it — so an anticipated cut is already in mortgage pricing by the announcement, and rates can rise afterward if the Fed signals fewer future cuts than hoped. Judging when to lock by Fed headlines is trading on news the bond market priced in days earlier. Should you lock now or wait?
Watching it yourself
Two public numbers tell most of the story: the 10-year Treasury yield and current MBS pricing — when both improve together, quoted rates genuinely have room to fall; when Treasuries improve but MBS lag, the spread is widening and quotes will disappoint. Ralo — an automated mortgage broker, not a lender — publishes its own quoted 30-year rate against the Freddie Mac national average weekly on the Rate Index, which makes the margin layer visible directly. The Ralo Rate Index
Ralo is an automated mortgage broker — not a lender — that compares multiple lenders from one application, earns a thin commission, and shows rate, APR, and fees upfront. Rates shown anywhere on this site are illustrative examples, not a loan approval, rate lock, or commitment. Available where licensed: California, Colorado, and Texas.