How Mortgage Rates Are Set
The rate you're quoted is built in three layers: the bond market sets the floor, your file adjusts it, and the lender adds its margin. Understanding the three tells you which parts you can move — and which you can't.
1. The bond market sets the floor
Most 30-year fixed mortgages are bundled into mortgage-backed securities (MBS) and sold to investors. What those investors will pay sets the base rate lenders can offer — so mortgage rates track the bond market, not the evening news. The 10-year Treasury yield is the usual reference point: when it rises, mortgage rates tend to follow, with a spread on top for the extra risk and the option to prepay.
Notably, the Federal Reserve does not set mortgage rates. The Fed moves the overnight rate banks charge each other, which steers short-term borrowing (credit cards, HELOCs). Long fixed mortgage rates move with the bond market's expectations — which is why a Fed cut can arrive on the same day mortgage rates rise.
2. Your file adjusts it
From that base, the lender prices your risk. Credit score, loan-to-value, loan type, property type and occupancy each nudge the rate through loan-level price adjustments. A strong file (high score, low LTV) prices near the base; a weaker one pays add-ons. These are the parts you can influence — a bigger down payment or a better score is real money.
3. The lender adds its margin
Finally, the lender adds the margin it needs to operate and profit. This is why two lenders quoting the same day, off the same bond market, can still differ by a quarter-point or more — and why shopping the same day matters. Comparing on the same day removes the market's daily noise and leaves only the difference that's actually about the lender.
Why our benchmark uses locked rates
Advertised rates are marketing; locked rates are what people actually got. That's why our benchmark leans on OBMMI, which is built from real locks, and why our Index strips out point-bought rates — so the number reflects the true market, not the best-case teaser. See exactly how we source it.
Common questions
Does the Federal Reserve set mortgage rates?
No. The Fed sets the overnight rate banks charge each other, which steers short-term credit like credit cards and HELOCs. Long fixed mortgage rates track the bond market, so they can even move the opposite way from a Fed decision on the same day.
Why did my rate change between two quotes?
Mortgage rates reprice daily, sometimes intraday, with the bond market. A quote from a different day is measuring the market's move, not the lender — which is why you should always compare quotes same-day.
How far above the 10-year Treasury are mortgage rates?
Mortgage rates sit above the 10-year Treasury yield by a spread that pays investors for prepayment and credit risk — historically around 1.7 percentage points, though it widens when markets are stressed.
Which parts of my rate can I actually influence?
Not the bond-market base, but the add-ons priced to your file: a higher credit score or a lower loan-to-value reduces the loan-level adjustments, and shopping lenders on the same day exposes differences in their margin.
By L.W. Martin, Founder — 20 years in the mortgage business, including 15 running his own brokerage. About → · Updated September 2026.