How Mortgage Rates Work: Treasuries, MBS, and Your Credit

Mortgage rates are not Fed rates

The single most common misconception about mortgage rates is that the Federal Reserve sets them. The Fed sets the federal funds rate — the overnight rate at which banks lend reserves to each other. That number directly influences short-term rates like credit cards, auto loans, and HELOCs. Mortgage rates are tied to longer-term instruments, primarily the 10-year Treasury yield and mortgage-backed securities (MBS), which can and do move in different directions from Fed policy.

When market participants expect the Fed to cut, long-term rates often fall before any meeting. When the Fed actually cuts, mortgage rates sometimes rise — because the cut was already priced in and the post-meeting news revealed the path forward. This is why 'the Fed cut so mortgage rates should drop' is so often wrong.

The bond market chain

Mortgage rates are set by the bond market. When you take out a mortgage, the lender almost always sells your loan to an investor as part of a mortgage-backed security. The MBS market trades in real time. As investor demand for MBS rises, prices rise and yields (rates) fall — and mortgage rates follow.

MBS yields track the 10-year Treasury with a spread (typically 1.5–2.5 percentage points). The spread widens during periods of stress (2008, March 2020, 2023's regional bank stress) and narrows in calm markets. The 10-year Treasury itself moves on inflation expectations, growth expectations, Fed policy guidance, and global flight-to-safety demand.

What moves rates day to day

Inflation data. CPI and PCE prints are the single biggest movers. Higher inflation pushes long-term yields up; lower inflation pulls them down.

Employment data. Strong jobs reports raise rates (the Fed will stay tight longer); weak reports lower them.

Fed speeches and minutes. The market parses every word from the Chair and FOMC members for forward guidance.

Geopolitical events. Flight-to-safety into Treasuries pushes yields down and mortgage rates down with them.

Auction results. The Treasury auctions new debt regularly. Weak demand pushes yields up.

How your personal rate is built

The 'national average' rate you see on news websites is roughly the par rate for an excellent borrower (760+ credit, 25%+ down, 30-year conforming). Your rate adds or subtracts from that baseline based on loan-level price adjustments (LLPAs) — surcharges Fannie and Freddie apply for credit, LTV, occupancy, and property type.

A 660-credit borrower with 5% down pays substantially more than a 760-credit borrower with 25% down on the same property — sometimes 1.0–1.5 percentage points in rate. This is why credit improvement before applying can move your monthly payment by hundreds.

Lender margin

Every lender adds a margin on top of the wholesale rate to cover operations and profit. This margin varies — large retail banks tend to charge more, mortgage brokers and credit unions tend to charge less, online lenders fall in between. Shopping at least 3 lenders typically reveals a 0.25–0.5% spread on the same borrower profile, which is meaningful money over 30 years.

Rate locks

Once you have a rate you like, you 'lock' it. A 30-day lock is standard; 60-day locks cost a bit more. The lock guarantees the rate even if market moves against you between lock and closing. If rates drop significantly after lock, many lenders offer a one-time 'float down' option for a fee.

Lock when (a) you have a contract and a clear closing date, and (b) rates are at or below your target. Locking too early ties you to one lender and one program before you have full information.

Historical context

Mortgage rates have spent most of the last 50 years between 5% and 10%. The 2.5–3.5% rates of 2020–2021 were historically exceptional, the product of extraordinary Fed intervention during COVID. Treating those rates as the baseline against which today's 6–7% rates are 'high' is misleading — for most of US history, today's rates would be considered moderate.

Where mortgage rates are headed

We don't make rate predictions on this site for one good reason: nobody is reliably right about them. What matters for your decision is the break-even math at today's rate, your honest hold period, and whether refinancing makes sense if rates drop later. The refinance guide walks through the break-even formula.