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Weighted Average Maturity (WAM)


Weighted Average Maturity (WAM) is a financial metric that calculates the average time until a portfolio’s securities or debt instruments mature, considering the possibility of early payments. This is weighted by the proportion of the total principal that each debt responsibility holds. WAM is commonly used in the analysis of mortgage-backed securities, bond and other fixed income portfolios.


The phonetics of the keyword: Weighted Average Maturity (WAM) is:- Weighted: /ˈweɪ.tɪd/ – Average: /ˈæv.ɚ.ɪdʒ/ – Maturity: /məˈtʊr.ə.ti/ – WAM: /wæm/

Key Takeaways

  1. Measurement of Average Maturity: Weighted Average Maturity (WAM) is a measure of the average amount of time until every dollar of the principal amount of a debt security or portfolio is expected to be repaid. It is a common tool used to assess the risk associated with fixed-income securities and portfolios.
  2. Impact on Risk and Return: A greater WAM implies that the security or portfolio is composed predominantly of long-term obligations. This could result in higher returns due to typically higher interest rates associated with long-term loans or bonds. However, it also poses a higher risk to the investor due to the longer time frame and the potential for greater fluctuations in the market.
  3. Use in Mortgage-Backed Securities (MBS): WAM is an especially important metric in the world of Mortgage-Backed Securities (MBS). It helps potential investors estimate the lifespan of a pool of mortgages, which is crucial in deciding whether or not to invest in a specific MBS. A longer WAM in MBS context could mean that homeowners are expected to take longer to reimburse their mortgages, which may delay the return of the principal to the investor.


Weighted Average Maturity (WAM) is an important concept in business and finance as it provides an assessment of the average time it will take for securities in a portfolio to mature, weighted in proportion to the dollar amount that is invested in each security. Understanding WAM is crucial for investors and portfolio managers as it helps in managing risks, especially those associated with interest rates and price volatility. A shorter WAM suggests that securities mature more quickly which may be less risky during periods of rising interest rates. However, longer WAM could yield higher returns during stable or declining rate environments. Thus, WAM is a key factor in determining the risk-return characteristic of a portfolio.


Weighted Average Maturity (WAM) is a key metric used by investors and financial managers to assess the maturity profile of financial assets or liabilities such as bonds or loans in a portfolio. This measure represents the average time it takes for securities in a portfolio to mature, factoring in the likelihood of early payments, and is important for making decisions about investment risk and return. Essentially, it helps to identify and quantify the sensitivity of investments to changes in interest rates, which in turn affects the returns.The purpose of WAM extends beyond simply providing an average maturity date. It assists in predicting the cash flow pattern, which can be particularly helpful for investors when the returns on their investments are affected by the time value of money. Understanding the WAM of a portfolio helps in effective financial planning and risk management. For instance, a portfolio with a longer WAM is typically considered to have a higher interest rate risk. This is because longer-term bonds are more affected by changes in interest rates than shorter-term bonds. So, WAM provides crucial information for asset-liability management and enables investors to adjust their investment strategies to balance risk and return effectively.


1. Investment in Bond Funds: Let’s say an investor puts his money into a bond fund that contains 10 different bonds. Each bond has a different maturity date: some might mature in 5 years, some in 10 years, some in 15 years, etc. To get a sense of the overall risk and return of the fund, the investor can calculate the Weighted Average Maturity (WAM), which reflects the average time it takes for all the bonds in the portfolio to mature, taking into account the proportion of the total investment that each bond represents. This helps in assessing risk and potential yield of the fund.2. Mortgage-Backed Securities (MBS): This is a type of asset-backed security that is secured by a mortgage. The maturity of these securities can be analysed via WAM. For instance, a security may include hundreds of mortgage loans with different maturing durations – some may be 10 years, others 15 or 30 years. Here, WAM represents the average time it takes for loans in the pool to repay their principal. For investors, a longer WAM indicates greater price volatility and interest rate risk.3. Corporate Debt Management: Suppose a corporation is managing its debt profile which includes multiple loans with different interest rates and maturity dates. The goal is to potentially refinance or pay off these loans in such a way as to minimize costs while effectively managing risk. Here, WAM can play a crucial role by letting the corporation know the average time until its debts become due, weighted by the proportion of total debt that each loan represents. This helps in strategic planning and risk management.

Frequently Asked Questions(FAQ)

What is Weighted Average Maturity (WAM)?

Weighted Average Maturity (WAM) is a measure of the average length of time until all securities in a fund or portfolio are expected to repay their principal, weighted in proportion to the dollar amount of each security.

How is WAM calculated?

WAM is calculated by multiplying the maturity of each security by its dollar amount, summing up these products, and then dividing by the total dollar amount of the portfolio or fund.

What does a high WAM signify?

A high WAM signifies that the securities in a portfolio or fund have longer maturity periods. This could mean higher interest rate risk, but potentially higher returns.

How does WAM affect the risk and return of a portfolio?

Portfolios with a higher WAM usually have higher yield as longer maturity bonds generally have higher interest rates. However, they also have more exposure to interest rate risk — if interest rates rise, the price of the bonds may fall more than shorter maturity bonds.

What is the difference between WAM and Weighted Average Life (WAL)?

Both WAM and WAL measure the average time until securities are expected to pay back their principal. However, WAM uses the final maturity date of each security, while WAL also takes into account the timing of principal repayments due before the final maturity date.

Why is WAM important to investors?

WAM helps investors understand the interest rate risk of their investment. By knowing the average maturity of the securities within a portfolio or fund, investors can make predictions about future performance in different interest rate environments.

Can WAM change over time?

Yes, WAM can change over time as the underlying securities in the portfolio or fund mature, or if new securities with different maturities are added or old ones are sold.

How is WAM related to bond funds?

For bond funds, WAM helps to estimate the fund’s sensitivity to changes in interest rates. If rates rise, a fund with a longer WAM is likely to decline in value more significantly than a fund with a shorter WAM.

Related Finance Terms

  • Portfolio Duration
  • Fixed-Income Securities
  • Cash Flow
  • Mortgage-Backed Securities (MBS)
  • Principal Repayment Schedule

Sources for More Information

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