A few factors determine mortgage interest rates. The most important one is the market. Rates are recalculated daily, and it can sometimes benefit you to wait for them to go down or hurry and lock in a rate when the day’s rates are very competitive. The second factor is borrower risk. Borrowers typically have to pay a higher rate if they are considered risky to the lender. The third factor is the lender. Different banks offer different rates, so it’s important to shop around for the best rate.