Mortgage Interest Rates - How Are They Determined?

Mortgage interest rates are the single-most importantis the 10-year Treasury Note. Treasury Notes earn a
factor determining the borrowing power of a potentialfixed rate of interest every six months until maturity
house buyer. When rates are very low, a borrowerissued in terms of 2, 5, and 10 years. The 10-year
can service a large amount of debt with a relativelyTreasury Note is a close approximation to mortgage
small payment, and when interest rates are very high,loans because most fixed-rate mortgages are paid off
a borrower can service a small amount of debt with abefore the 30 year maturity with 7 years being a
relatively large payment.typical payoff timeframe.
Mortgage interest rates are determined by marketThe difference in yield between a 10-year Treasury
forces where investors in mortgages andNote and a 30-day Treasury Bill is a measure of
mortgage-backed securities bid for these assets. Theinvestor expectation of inflation, and the difference
rate of return demanded by these investorsbetween the yield on a 10-year Treasury Note and the
determines the interest rate the originating lender willprevailing market mortgage interest rate is a measure
have to charge in order to sell the loan in theof the risk premium.
secondary market. Some lenders still hold mortgages inInflation reduces the buying power of money over
their own investment portfolio, but these mortgagestime, and if investors must wait a long period of time to
and mortgage rates are subject to the same supplybe repaid, as is the case in a home mortgage, they will
and demand pressures generated by the secondarybe receiving dollars that have less value than the ones
mortgage market.they provided when the loan was originated. Investors
Mortgage interest rates are determined by investordemand compensation to offset the corrosive effect
demands for risk adjusted return on their investment.of inflation. This is the inflation premium.
The return investors demand is determined by threeThe risk premium is the added interest investors
primary factors: the riskless rate of return, the inflationdemand to compensate them for the possibility the
premium and the risk premium.investment may not perform as planned. Investors
The riskless rate of return is the return an investorknow exactly how much they will get if they invest in
could obtain in an investment like a short-termTreasury Notes, but they do not know exactly what
Treasury Bill. Treasury Bills range in duration from athey will get back if they invest in residential home
few days to as long as 26 weeks. Due to their shortmortgages or the investment vehicles created from
duration, Treasury Bills contain little if any allowance forthem. This uncertainty of return causes them to ask
inflation. A close approximation to this rate is thefor a rate higher than that of Treasury Notes. This
Federal Funds Rate controlled by the Federal Reserve.additional compensation is the risk premium.
It is one of the reasons this activities of the FederalThus, mortgage interest rates are a combination of the
Reserve are watched so closely by investors.riskless rate of return, the risk premium and the inflation
The closest risk-free approximation to mortgage loanspremium.