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Guide

How Mortgage Rates Are Actually Determined

How lenders price mortgages using Treasuries, MBS, and Freddie Mac's weekly PMMS survey. Educational mechanics, not a quote or a forecast.

Published: 2026-09-14

Key takeaways

  • Freddie Mac's Primary Mortgage Market Survey is a weekly national average of application-stage rates from Loan Product Advisor files, not a personal quote and not a closing rate.
  • PMMS aggregates conventional, conforming, single-family purchase applications and publishes on Thursdays at noon Eastern. The sample week runs from the prior Thursday through Wednesday.
  • The Federal Reserve's policy rate is a short-term overnight rate. Long-term mortgage pricing usually tracks the 10-year Treasury yield plus a mortgage-backed securities spread, then a lender's own credit, points, and fee overlay.
  • A headline national average is not an APR and not a lock. The CFPB says APR also reflects points, broker fees, and other charges to get the loan.

Published: 2026-09-14

A mortgage rate is a price a lender offers on a specific file, on a specific day, for a specific product. It is not a single number the government assigns, and it is not the same thing as a weekly national average.

This page explains the chain that usually sits behind that price: bond yields, mortgage-backed securities, Freddie Mac's Primary Mortgage Market Survey, and the borrower-level overlays that turn a market level into a Loan Estimate. It does not quote today's market and it does not forecast where rates go next.

Does the Federal Reserve set mortgage rates?

No. The federal funds rate is the overnight rate banks charge each other. Mortgage loans are long-term, amortizing contracts. Lenders fund them in a market that prices years of interest-rate and prepayment risk.

When the Fed changes policy, short-term rates move first. Longer yields, including the 10-year Treasury, may adjust as investors rewrite inflation and growth expectations. Mortgage rates often move with those longer yields. They do not move one-for-one with each Fed meeting.

Treat Fed headlines as context, not a formula. A lender still has to price your credit, loan-to-value, points, lock period, and product. Nothing in that chain is a promise that a future Fed decision will lower or raise the rate on your file.

How do Treasuries and mortgage bonds enter the price?

Most conventional home loans are pooled into mortgage-backed securities and sold to investors through Fannie Mae, Freddie Mac, or Ginnie Mae. Investors compare those bonds to safer government debt, especially the 10-year Treasury.

The extra yield investors demand on mortgage bonds versus Treasuries is the MBS spread. When that spread widens, mortgage rates can sit higher even if Treasury yields are unchanged. When the spread tightens, mortgage rates can ease relative to Treasuries. That is market plumbing, not a forecast.

A personal rate still sits above that market level. Credit, occupancy, property type, loan size, and points all change the overlay. Compare written Loan Estimates, not a bond yield you saw on a chart. Our national rate snapshot shows how this site sources weekly averages. It is not your quote.

What is Freddie Mac's Primary Mortgage Market Survey?

Freddie Mac's Primary Mortgage Market Survey, or PMMS, is the industry's long-running weekly national average for 30-year and 15-year fixed rates. Since November 17, 2022, Freddie Mac has built PMMS from purchase applications submitted to Loan Product Advisor rather than from a phone survey of lenders.

Freddie Mac writes that results are "based on the mortgage rate collected from thousands of loan applications submitted to Freddie Mac through Loan Product Advisor (LPA) from lenders across the country when a borrower applies for a mortgage." The published figure is an application-stage average. It is not the rate at origination, and not every application closes.

The sample is conventional, conforming, single-family purchase activity inside FHFA loan limits. The application week runs from 12:00 a.m. Eastern the prior Thursday through 11:59 p.m. Eastern Wednesday. Results post on Thursday at noon Eastern, or Wednesday when Thursday is a U.S. holiday.

Rate note: a PMMS print is a survey average for a filtered set of files. It is not a quote, a lock, or a guaranteed APR. Your written Loan Estimate is the document that carries a personal rate.

Why does your quoted rate differ from the weekly average?

PMMS is built around a prime, conforming, purchase profile. Jumbo, refinance, FHA, VA, and low-down-payment files sit outside that box. Daily lender sheets also move inside the survey week, so a Thursday print can lag what a loan officer is offering on Friday.

The CFPB separates the interest rate from APR. The interest rate is the yearly cost of borrowing. APR "reflects the interest rate, any points, mortgage broker fees, and other charges that you pay to get the loan." Two files with the same note rate can have different APRs.

Lock period, discount points, and lender credits change the cash you bring to closing. See how to compare points and APR and how a rate lock works. Then price a payment in the mortgage payment calculator using the Loan Estimate rate, not a national average.

What usually belongs on a pricing worksheet?

  • Product and term (for example 30-year fixed conventional), not a mixed ARM and fixed pair.
  • The same assumed lock period and the same points or credits.
  • Credit, loan-to-value, occupancy, and property type the lender actually used.
  • APR and cash to close from the Loan Estimate, not a flyer rate.

If you are still choosing a structure, the ARM versus fixed explainer covers how those products price risk differently. None of those pages predicts the next move in the bond market.

Disclaimer: this guide is for general education. HomeMortgageOnline is not a lender, broker, or loan originator. It does not take applications, lock rates, or give financial advice. Real offers vary by credit, down payment, loan type, points, fees, and market conditions.

Sources

  1. Freddie Mac, Primary Mortgage Market Survey (PMMS) methodology and FAQs - https://www.freddiemac.com/pmms
  2. Freddie Mac, Newly Enhanced Mortgage Rate Survey Explained (November 3, 2022) - https://www.freddiemac.com/research/insight/20221103-freddie-macs-newly-enhanced-mortgage-rate-survey
  3. Consumer Financial Protection Bureau, What is the difference between a mortgage interest rate and an APR? - https://www.consumerfinance.gov/ask-cfpb/what-is-the-difference-between-a-mortgage-interest-rate-and-an-apr-en-135/
  4. Consumer Financial Protection Bureau, What's a lock-in or a rate lock on a mortgage? - https://www.consumerfinance.gov/ask-cfpb/whats-a-lock-in-or-a-rate-lock-en-143/

Frequently asked questions

Who actually sets mortgage rates?

No single office sets your rate. Lenders price against bond yields and mortgage-backed securities, then add credit, points, fees, and lock terms. Freddie Mac's PMMS only reports a weekly national average of application-stage conforming purchase rates. That average is not a personal quote or a lock.

Does the Federal Reserve set the 30-year mortgage rate?

No. The federal funds rate is an overnight bank rate. Mortgage pricing usually tracks longer yields, especially the 10-year Treasury, plus a mortgage-bond spread. A Fed decision can influence those yields. It does not assign the rate on a Loan Estimate.

What does Freddie Mac's PMMS measure?

PMMS is a Thursday national average of conventional, conforming, single-family purchase applications submitted to Loan Product Advisor. The sample week runs Thursday through Wednesday. Freddie Mac notes it is an application-stage average, not the rate at origination and not a guarantee any file will close.

Why is my lender's rate different from the weekly average?

PMMS filters for a prime conforming purchase profile. Your credit, down payment, loan type, points, and lock period can sit outside that box. Daily sheets also move inside the survey week. Compare APR and cash to close on written Loan Estimates, not the headline average.

Is a national average the same as APR?

No. The CFPB says the interest rate is the yearly cost of borrowing and does not include fees. APR adds points, broker fees, and other charges to get the loan. A survey average is neither figure for your file. Nothing here is a rate lock or a guaranteed APR.