Adjustable rates transfer part of the interest rate risk from the lender to the borrower, and thus are widely used where fixed rate funding is difficult to obtain or prohibitively expensive. Since the risk is transferred to the borrower, the initial interest rate may be from 0.5% to 2% lower than the average 30-year fixed rate; the size of the price differential will be related to debt market conditions, including the yield curve.

Additionally, lenders in many markets rely on credit reports and credit scores derived from them. The higher the score, the more creditworthy the borrower is assumed to be. Favorable interest rates are offered to buyers with high scores. Lower scores indicate higher risk for the lender, and higher rates will generally be charged to reflect the (expected) higher default rates.

A partial amortization or balloon loan is one where the amount of monthly payments due are calculated (amortized) over a certain term, but the outstanding principal balance is due at some point short of that term. This payment is sometimes referred to as a "balloon payment" or bullet payment. The interest rate for a balloon loan can be either fixed or floating. The most common way of describing a balloon loan uses the terminology X due in Y, where X is the number of years over which the loan is amortized, and Y is the year in which the principal balance is due.