September 17, 2026 Mortgage Rates: Lock Risk

Freddie Mac’s September 17, 2026 release put average mortgage rates at 6.95% for a 30-year fixed loan and 6.26% for a 15-year fixed loan. These benchmarks reflect the preceding application week; they do not establish a borrower-specific quote. For purchase files near closing, they warrant refreshing unlocked pricing and checking existing locks’ expiration dates and conditions.

Which applications does September 17 PMMS cover?

Applying Freddie Mac’s published collection rule, the observation window runs from September 10 through September 16, starting at midnight Thursday and ending at 11:59 p.m. Wednesday, Eastern time. The Primary Mortgage Market Survey, or PMMS, uses submissions to Loan Product Advisor, Freddie Mac’s automated underwriting system. It measures application-stage rates, rather than completed closings or exclusively new rate locks. Freddie Mac’s methodology note, published November 3, 2022, explains that distinction.

The September 17 release describes the survey’s target as conventional, conforming, fully amortizing home purchase loans for borrowers with 20% down and excellent credit. A different borrower profile or loan program calls for separate pricing.

Because observations span a week, the average cannot establish an executable September 17 offer or isolate the effect of one policy announcement. That limitation also leaves the next rate move an open question.

How much did the weekly benchmarks rise?

Both fixed-rate benchmarks increased from the previous release:

These are the current and prior-week figures reported in the dated Freddie Mac release. The increases equal 19 and 17 basis points, respectively.

The comparison gives teams a reason to revisit pricing assumptions. It does not establish that every lender raised every offer by those amounts. Our mortgage-rate reports provide release-by-release context; the mortgage pricing and rate explanations address how to read individual offers.

Payment sensitivity on a $400,000 loan

Illustration, not a loan offer: assume a $400,000 principal balance, a fully amortizing fixed-rate loan, monthly payments and no financed fees. Hold the loan amount and repayment term constant within each row, changing only the interest rate. The calculation excludes property taxes, homeowners insurance, mortgage insurance, association charges and closing costs.

These are our monthly principal-and-interest calculations using the reported rates, rounded to cents. The smaller weekly increase for the 15-year example does not mean a lower payment: repaying the same balance over fewer months produces the larger payment shown.

Compare payments at the two benchmark rates, then replace those assumptions with the lender’s actual offer.

The illustration helps estimate an unlocked file’s payment exposure before repricing. Whether roughly $51 more each month matters to a particular 30-year file depends on its actual terms and the buyer’s budget. The table does not determine qualification.

Refresh the unlocked offer’s payment and cash requirement

For an unlocked purchase file, request updated pricing for the same loan amount, program, term and intended closing date. Record when the quote was prepared and the lock period offered so the comparison shows what changed.

Check points and lender credits alongside the rate. Discount points trade more cash at closing for a lower rate; rate-linked lender credits trade a higher rate for lower upfront costs. Ask competing lenders to quote the same points or credits, as the CFPB’s points-and-credits guidance explains. PMMS does not report average points or origination fees, according to its methodology.

Use the updated offer to refresh both the complete payment and the cash-to-close estimate. Principal and interest exclude costs such as taxes and insurance. Cash to close includes the down payment and closing costs after applicable credits and adjustments. The CFPB’s Loan Estimate explainer identifies those components.

If the buyer’s payment ceiling or available cash is tight, ask the loan officer to reassess the file using the new offer before relying on the earlier budget.

What can change under an existing rate lock?

A valid lock protects the agreed interest rate through its specified period when the application remains unchanged and closing occurs on time. A higher PMMS average alone does not replace that rate. Check the lock status and expiration on page 1 of the Loan Estimate. CFPB’s rate-lock guidance explains the conditions.

Application changes can still affect a locked rate, including a different loan amount or down payment, changed credit information, an unexpected appraisal or income the lender cannot verify. Locking the rate also leaves some closing expenses subject to change, including insurance premiums and initial escrow deposits. CFPB’s closing-cost guidance distinguishes those issues.

If the closing timetable has slipped, ask the lender for written extension terms. Extensions can cost money, and a later market decline does not automatically entitle a locked borrower to a lower rate; lender policies vary, as the CFPB explains.

For the next pipeline review, record each file’s pricing date, lock status, expiration and unresolved closing dependencies. Assign fresh pricing to unlocked files and a review of timing and conditions to locked files.