What Goes Into a Mortgage Rate? Market and Borrower Factors

Someone once asked how mortgage rates are actually calculated, and it is a fair question. The number on a loan offer looks like one decision. In practice it is the sum of several layers, some set by markets and some by the borrower's own situation.

Key takeaways

• A mortgage rate combines market-wide factors with personal factors, so it is not set by any single decision.
• Market-wide forces include longer-term borrowing costs, mortgage-backed securities pricing and prepayment risk, funding and operating costs, and lender margins. Short-term central bank policy and inflation expectations can influence longer-term yields, but they do not translate one-for-one into a fixed mortgage rate.
• The Consumer Financial Protection Bureau lists credit, down payment, loan amount and term, and points or credits among the personal factors.
• A change in one layer can be offset by another, which is why rates do not always move in step with central bank announcements.
• Comparing Loan Estimates from different lenders on the same day is a practical way to see how these layers show up in an offer.

The market-wide layers

These forces interact, and their effects vary over time. Research from the Federal Reserve and Freddie Mac describes how longer-term Treasury yields, mortgage-backed securities pricing, prepayment risk, funding and operating costs, and lender margins can contribute to primary mortgage rates.

1. Longer-term yields. Fixed mortgages last for years. Longer-term Treasury yields are one market reference, and mortgage rates often move with them without matching them exactly.
2. Mortgage-backed securities. Many mortgages are pooled into securities. Their yields and the spread investors require relative to Treasury securities affect the prices lenders can receive when selling loans.
3. Prepayment and hedging risk. Borrowers may repay early, including by refinancing when rates fall. Investors and lenders account for that uncertainty and the hedging it requires.
4. Funding, origination and servicing costs. Making, funding and managing a loan involves costs that can vary across lenders and over time.
5. Lender margin and competition. Lenders set prices based partly on their own margins, capacity and appetite for particular loans.

These forces can move in different directions. A change in the short-term policy rate may coincide with different moves in long-term yields, mortgage-backed securities pricing, lender costs or margins. That is one reason fixed mortgage rates do not always move in step with central bank announcements.

The personal layers

On top of the market is the borrower. The Consumer Financial Protection Bureau lists several factors that determine the rate a lender offers:

• Credit. Lenders typically weigh credit scores heavily. Errors on a credit report can lower a score, so the CFPB suggests checking reports well before applying.
• Down payment. A larger down payment generally lowers lender risk, which can help the rate.
• Loan amount and term. The CFPB notes that shorter-term loans have lower interest rates and lower overall costs but higher monthly payments, and that very small or very large loans can carry higher rates.
• Points and lender credits. Paying points can lower the rate, while lender credits can lower upfront costs in exchange for a higher rate.
• Market conditions on the day. Rates change often, and a rate lock sets the rate for a period.

For an adjustable-rate mortgage, the rate after the initial period is built from an index, a rate that moves with market conditions, plus a margin set by the lender, and caps can limit how much it rises.

Why this helps when shopping

Because so many pieces are involved, two lenders can quote different rates for the same borrower on the same day. Their costs, margins and appetite for certain loans can differ. A useful way to compare is to request Loan Estimates from several lenders at about the same time and line up the rate, points, fees and monthly payment.

Questions worth asking

• Which parts of my rate come from the market, and which come from my own profile?
• If I improve my credit or increase my down payment, how much could that change the offer?
• What do points or lender credits do to my rate and my upfront costs?
• Is the rate fixed, or could it change later?
• How long does the rate lock last, and what happens if closing is delayed?

A mortgage rate is not one number handed down from above. Looking at its parts makes it easier to see which pieces a borrower can influence and which are simply the market's weather.

Common questions

Who decides my mortgage interest rate?

No single party does. The rate reflects conditions in financial markets, the lender's costs and margin, and your own profile, such as credit, down payment, and loan size and term.

What is the term premium?

It is the additional yield investors ask for in return for lending over a longer period instead of a shorter one, because more can change over time. When it rises, long-term yields can rise, and mortgages are long-term loans.

Does my rate change when the central bank changes its policy rate?

A fixed rate you already have does not change. New mortgage rates may move, but the effect is indirect and may be accompanied by changes in longer-term yields, mortgage-backed securities pricing, lender costs or margins.

NIFE provides general financial education. LendsightAI and Debt Done Date are separate for-profit partners; optional services may have a fee.