The Fed's rate is 3.5%. Your mortgage is 6.67%. Here's what sits in between.

There is a widely held belief that when the Federal Reserve cuts interest rates, mortgage rates fall. It is intuitive, it is repeated constantly, and it is close enough to true that correcting it feels pedantic.

It is also the reason a lot of people are waiting for something that may not arrive in the form they expect.

The three rates, and what each one does

The Federal Reserve sets the first one. It is an overnight rate — the cost of money for one night, between banks. It is the shortest-term interest rate that exists in any meaningful sense.

Your mortgage is the opposite: a commitment measured in decades. Its price is set by what investors demand to hold long-dated US debt, plus compensation for everything that makes a mortgage riskier than a Treasury bond.

The spread, calculated

That ~2 percentage point spread is not a fee anyone charges. It is the sum of several distinct compensations:

• Prepayment risk. You can refinance whenever rates fall, but you cannot be forced to pay more when they rise. The investor holding your mortgage has given you a valuable option and charges for it.
• Credit risk. Households default; the US Treasury does not, in dollars.
• Servicing and origination. Someone administers the loan for thirty years and is paid to do it.
• Guarantee fees. Where a loan is packaged into a government-backed security, the guarantor charges for the guarantee.
• Who is buying. The demand for mortgage-backed securities from banks and other large investors moves the spread independently of anything the Fed does.

Why cuts do not automatically pass through

When the Fed cuts its overnight rate, it directly affects short-term borrowing: credit cards, floating-rate business debt, home equity lines. Long-term rates respond to something else — expectations about inflation and growth over the entire life of the loan.

What this means in a monthly payment

That difference is worth watching for. It is not worth waiting indefinitely for, because the thing that would deliver it is a fall in long-term yields, and long-term yields are being held up by the same 3.4% inflation rate that is keeping the Fed on hold.

What to actually watch

• The 10-year Treasury yield, not the Fed funds rate. It is published continuously and it is the input that matters.
• The spread itself. If it narrows toward historical norms, mortgage rates can fall even with Treasury yields unchanged.
• Inflation expectations, which drive long-term yields more than any single Fed meeting does.
• The 15-year alternative. At 5.96% versus 6.67%, the shorter term costs 71 basis points less — a meaningful difference for borrowers who can carry the higher monthly payment.