Risk-free interest rate

Risk-free interest rate is the theoretical rate of return of an investment with no risk of financial loss. One interpretation is that the risk-free rate represents the interest that an investor would expect from an absolutely risk-free investment over a given period of time.

Since the risk free rate can be obtained with no risk, any other investment will have additional risk.

In practice to work out the risk-free interest rate in a particular situation, a risk-free bond is usually chosen that is issued by a government or agency where the risks of default are so low as to be negligible.

Risk components

Risks that may be included are default risk, currency risk, and inflation risk.

Theoretical measurement

As stated by Malcolm Kemp in Chapter five of his book Market Consistency: Model Calibration in Imperfect Markets, the risk-free rate means different things to different people and there is no consensus on how to go about a direct measurement of it.

One interpretation of the theoretical risk-free rate is aligned to Irving Fisher's concept of inflationary expectations, described in his treatise The Theory of Interest (1930), which is based on the theoretical costs and benefits of holding currency. In Fisher’s model, these are described by two potentially offsetting movements:

Interest rate

An interest rate is the rate at which interest is paid by borrowers (debtors) for the use of money that they borrow from lenders (creditors). Specifically, the interest rate is a percentage of principal paid a certain number of times per period for all periods during the total term of the loan or credit. Interest rates are normally expressed as a percentage of the principal for a period of one year, sometimes they are expressed for different periods such as a month or a day. Different interest rates exist parallelly for the same or comparable time periods, depending on the default probability of the borrower, the residual term, the payback currency, and many more determinants of a loan or credit. For example, a company borrows capital from a bank to buy new assets for its business, and in return the lender receives rights on the new assets as collateral and interest at a predetermined interest rate for deferring the use of funds and instead lending it to the borrower.

Interest-rate targets are a vital tool of monetary policy and are taken into account when dealing with variables like investment, inflation, and unemployment. The central banks of countries generally tend to reduce interest rates when they wish to increase investment and consumption in the country's economy. However, a low interest rate as a macro-economic policy can be risky and may lead to the creation of an economic bubble, in which large amounts of investments are poured into the real-estate market and stock market. In developed economies, interest-rate adjustments are thus made to keep inflation within a target range for the health of economic activities or cap the interest rate concurrently with economic growth to safeguard economic momentum.