- The federal funds rate is an overnight rate between banks. No mortgage is priced off it directly.
- Thirty-year mortgages are priced off mortgage-backed securities, which trade alongside the 10-year Treasury. Both move on expectations, often before the Fed acts.
- What a borrower should watch is the 10-year yield and the spread between it and the 30-year fixed average. That spread is currently tight, so rates are moving nearly one-for-one with the bond market.
What the Fed actually controls
The Federal Open Market Committee sets a target range for the federal funds rate, the rate banks charge each other to borrow reserves overnight. It moves credit cards, home equity lines and some adjustable-rate loans quickly because those are tied to the prime rate, which follows the funds rate. A 30-year fixed mortgage is not.
Where a 30-year fixed rate comes from
When you close, your loan is almost always pooled with thousands of others into a mortgage-backed security and sold to investors. The price investors will pay for that bond today is what sets the rate a lender can offer you today. Those investors are choosing between mortgage bonds and Treasuries, so the 10-year Treasury yield, the closest thing in maturity to how long people actually keep a mortgage, is the benchmark. Mortgage rates sit above the 10-year by a spread that compensates investors for prepayment risk and credit risk.
Why September's hike barely moved anything
By the time the FOMC voted, the bond market had already priced a hike in for weeks. The 10-year had climbed roughly a full point from its February low and touched 5.04% ahead of the meeting. Freddie Mac's survey rate was already at 6.95%, the fourth straight weekly increase. The decision confirmed expectations rather than changing them, which is why the reaction was muted. Markets react to surprises, and this wasn't one.
The part that mattered more than the vote was the projection: a majority of officials open to another hike this year. That is forward guidance, and forward guidance moves the 10-year, which moves your rate. The chair's press conference is where that lives, which is why I link it on the Market Intelligence page after every meeting.
The number to watch: the spread
Subtract the 10-year yield from the 30-year fixed average. Historically that spread ran around 1.7 points. In 2023 and 2024 it blew out toward 3.0 as investors demanded more for prepayment risk. As of this writing it is about 2.0, which is tight by recent standards. A tight spread means two things for a borrower: mortgage rates will track the 10-year almost exactly from here, and there is little cushion for lenders to improve pricing unless yields fall first.
If you close inside 30 days, we lock; the bond market's near-term direction is not worth betting a closing on. Past 30 days, I watch the 10-year against its moving averages and the next data release on the calendar, and I call you when the picture changes. A seller-paid temporary buydown is often a better use of leverage than waiting for the Fed, because the seller's concession is certain and the Fed's next move is not.
Sources
Federal Reserve, FOMC press conference, September 16, 2026 · Freddie Mac Primary Mortgage Market Survey · U.S. Treasury daily yield curve · FRED, MORTGAGE30US
This article is Dave's interpretation of published data, written and reviewed by him. It is educational, not a rate quote or investment advice.
