How Do Mortgage Interest Rates Work, and What Moves Them?

A mortgage interest rate is built in two layers. The base layer tracks a benchmark that reflects the broader cost of long-term borrowing - in markets like the United States, mortgage rates track most closely with yields on long-term government bonds, since mortgages and long bonds compete for the same pool of investor money and carry similar multi-year time horizons. On top of that base rate, lenders add a margin that reflects the individual borrower's risk: credit score, down payment size, debt-to-income ratio, loan term and whether the rate is fixed or adjustable all shift where an individual quote lands relative to the market average. Borrowers can also pay “points” upfront - a fee equal to a percentage of the loan amount - to buy the interest rate down for the life of the loan, a trade-off that only pays off if the borrower keeps the loan long enough for the monthly savings to exceed the upfront cost.

A common misconception is that mortgage rates move in lockstep with a central bank's benchmark short-term rate. In practice, the relationship is looser: a central bank's rate decisions influence investor expectations for inflation and future growth, and those expectations - not the short-term rate itself - are what get priced into long-term bond yields and, in turn, mortgage rates. This is why mortgage rates can rise even after a central bank cuts short-term rates, if the market interprets the cut as a sign of persistent inflation risk, or fall even without a hike, if lending demand keeps investors piling into long-term government bonds and pushing their yields down. Borrowers comparing loan offers should also distinguish the interest rate from the APR (annual percentage rate), which folds in lender fees and closing costs to give a fuller picture of the loan's total cost - a lower headline rate with high upfront fees can end up more expensive than a slightly higher rate with none.