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Average Life


Average Life, in finance, refers to the average length of time that an investor needs to keep a bond in their portfolio until it is repaid. It is a measure of bond repayment that accounts for potential early payments, not merely the bond’s maturity date. It is used in debt securities and is important in determining the risk and return on bonds.


The phonetic pronunciation of “Average Life” is /ˈævɝːdʒ laɪf/.

Key Takeaways

<ol> <li>Understanding Average Life : Average life, also known as the weighted-average life (WAL), is the average period of time that each dollar of unpaid principal on a loan, a mortgage or an amortization-based investment, remains outstanding. </li> <li>Calculation and Tie-in with Investments : Determining the average life of a loan or investment helps predict the value or potential return of the investment. It is calculated by multiplying each amount of principal received by the period at which it is received, and then summing these figures and dividing by the total amount of principal.</li> <li>Influence on Financial Decisions : Average life is an important concept in the financial sector. It is a key component used to calculate the yield to maturity of a debt instrument, and is therefore used to make investment decisions and assess the risks and returns of different financial products.</li></ol>


Average Life is an important business/finance term as it measures the expected time in years it will take to receive the repayments of the principal amount on a debt security such as a bond or a mortgage. This term is vital for investors and financial institutions as it helps them calculate the risk and return associated with securing bonds, loans or other types of debt instruments. Having knowledge of the average life of a bond or a loan can greatly influence their investment strategy and decision-making process by estimating the period of time their funds will be tied up and when they can expect their principal investment to be returned. In essence, it provides a means to assess the timing of cash flows and the potential impact of interest rate changes.


The average life, also termed as the weighted average maturity, often serves as a critical tool in the realm of debt securities, particularly in the context of bond investments and fixed income markets. The purpose of determining the average life of a bond is to ascertain the period over which the bulk of the repayment of principal from a loan, bond, or mortgage is expected to be received. This measure aids investors to strategize their investment decisions effectively by providing a more concrete sense of the bond’s price sensitivity to shifts in interest rates. The concept is particularly essential for financial instruments that make regular periodic payments, enabling investors to plan their future cash flows meticulously and manage their risk exposure better.Average life is also applied extensively when it comes to analysing loans, especially asset-backed securities such as mortgage-backed securities. When it comes to mortgage or asset-backed securities, the average life calculation is instrumental in estimating the cash flow patterns, as the loan repayment might fluctuate due to the active role borrowers play (prepayment of loans). Therefore, by understanding the average life of a bond or a loan, investors can effectively gauge the rate of returns on their investments and undertake informed decisions that align with their financial goals and risk tolerance. Thus, average life is a valuable tool for measuring a financial instrument’s lifespan, providing financiers with an edge in managing their portfolio diversity, risk analysis, and investment strategies.


1. Mortgage Loans: Assume a person takes out a mortgage loan for $500,000 at a fixed interest rate for 30 years. The average life of this loan would be 30 years because that’s the period over which the principal is scheduled to be completely paid off. However, if the borrower makes additional principal repayments, the average life of the loan will decrease because the full principal would be paid off sooner.2. Corporate Bonds: Consider a corporation that issues a 10-year bond worth $1 million with the condition that it will make annual interest payments and repay the principal at the maturity. The average life of this bond will be 10 years. However, if the bond includes a feature that allows the issuer to buy back the bond after 5 years, the average life of the bond would depend on whether or not the issuer exercises that option.3. Auto Loans: An individual takes out an auto loan to finance a car purchase. The loan is set up to be paid back over 5 years. As long as the borrower makes only the required payments on the loan, the average life of the loan will be 5 years. However, if the borrower makes extra payments toward the principal, the loan will be repaid faster, reducing the average life of the loan.

Frequently Asked Questions(FAQ)

What is the term Average Life in finance and business?

Average life is a term used in finance and business to refer to the average length of time that each dollar of unpaid principal on a loan, a mortgage or an amortizing bond remains outstanding.

How is Average Life calculated?

Average life is calculated by averaging together the maturity dates of each portion of principal amount tied to a debt security, taking into account the proportion of the principal amount that each portion represents.

Why is the concept of Average Life important?

Average life is a crucial measurement for investors in deciding on a particular bond or another type of security. Investors always want to know how long their money will be tied up and when they can expect to receive their principal back.

Does Average Life account for the potential early repayment risks?

Yes, average life does consider the prepayment risk or early repayment risk into the calculation because it affects the average length of time that each dollar of unpaid principal remains outstanding.

Can the Average Life of a loan or a bond change?

Yes, the average life can change if the borrower makes additional principal payments before their scheduled due date.

How does the Average Life affect the yield of a bond or a debt security?

The longer the average life, the greater the duration risk or interest rate risk, which could affect the yield of the bond. Typically, the longer the average life, the higher the yield required by investors.

Can Average Life be used for benchmarking?

Yes, average life is often used as a benchmark for comparing loans, bonds, or other types of debt securities. It helps investors evaluate the relative risk and return of different securities.

Related Finance Terms

  • Amortization Schedule
  • Principal Payment
  • Aggregate Outstanding Balance
  • Interest Payment Schedule
  • Bond Maturity

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