Weighted Average Maturity (WAM): Understanding Its Importance in Fixed-Income Investments

When a person invests in bonds or debt funds, the first question is usually, “How much return will it give?” After that, they may check the rating, company name and maturity date. All these points matter. But there is one more thing that can help an investor understand the investment better. That is Weighted Average Maturity.

A bond portfolio usually does not have only one bond. It may have many bonds. Some may mature in a few months. Some may mature after 2 years. Some may mature after 5 years or more. So, it becomes difficult to know the overall maturity of the portfolio by looking at every bond one by one.

This is where Weighted Average Maturity, or WAM, helps. It gives one simple number that tells how long the portfolio may take to mature on average. It also considers how much money is invested in each bond. So, it gives a more practical picture of the portfolio.

What Is Weighted Average Maturity (WAM)?

What Is Weighted Average Maturity? In simple words, it is the average time left for all bonds in a portfolio to mature. But it is not a plain average. It gives more importance to the bonds where more money is invested.

For example, suppose a portfolio has three bonds. One bond forms 60% of the portfolio. The other two bonds form 20% each. In this case, the 60% bond will have more impact on the WAM because a larger part of the money is invested there.

This is why WAM is useful. It shows where most of the money is placed and how long that money may remain invested.

If most of the portfolio is invested in bonds that mature after 5 years, the WAM will be higher. If most bonds mature within 1 year, the WAM will be lower. So, WAM tells whether the portfolio is short-term, medium-term or long-term.

It does not mean that every bond will mature on the same date. It only gives one average number for easier understanding.

Why WAM Matters In Fixed-Income Investing

WAM matters because time is very important in fixed-income investments. A bond maturing in 6 months and a bond maturing in 6 years will not behave the same way.

A short-term bond usually has less price movement. A long-term bond may move more when interest rates change. This is why an investor should understand the maturity profile before choosing a debt fund or bond portfolio.

Weighted Average Maturity helps answer a simple question: how long is the portfolio generally invested for?

This is useful when an investor is planning for a goal. For example, if money is needed after one year, a portfolio with a very high WAM may not match that need. The bonds inside the portfolio may mature much later. This can create more price movement if interest rates change.

But if the investor has a goal that is 3 to 5 years away, a medium or longer WAM may be reviewed. Still, WAM should not be checked alone. The investor should also look at credit rating, duration, yield, issuer quality and liquidity.

WAM also helps when comparing two debt funds. One fund may show a higher return, but it may also have a higher WAM. This means the fund may be taking longer maturity exposure. So, return should not be the only thing an investor looks at.

How To Calculate WAM (Formula + Worked Example)

Calculating WAM is not difficult. An investor needs two things. First, the share of each bond in the portfolio. Second, the time left for each bond to mature.

The formula is:

WAM = Sum of each bond’s portfolio weight × remaining maturity

Here is a simple example:

Now, add the weighted maturity numbers:

0.80 + 1.40 + 1.50 = 3.70 years

So, the WAM of this portfolio is 3.70 years.

This does not mean all bonds will mature after 3.70 years. Bond A will mature in 2 years. Bond B will mature in 4 years. Bond C will mature in 6 years. WAM only gives one combined average for the full portfolio.

While Calculating WAM, larger holdings matter more. A small bond with a long maturity may not change WAM much. But a large bond with a long maturity can increase the WAM quickly.

What A Higher Vs Lower WAM Tells Investors

A higher WAM usually means the portfolio has more long-term bonds. These bonds take more time to mature. Because of this, they may react more when interest rates change.

A lower WAM usually means the portfolio has more short-term bonds. These bonds mature sooner. So, they may show less price movement compared to long-term bonds.

For example, if an investor wants to keep money only for a few months, a low WAM portfolio may be easier to understand. It may also match short-term needs better.

If the investor is planning for a goal after many years, a higher WAM may be studied. But the investor should still check the risk, rating, liquidity and duration before deciding.

In simple words, higher WAM means longer maturity exposure. Lower WAM means shorter maturity exposure. The right WAM depends on the investor’s time period and comfort with risk.

WAM And Interest Rate Risk

Interest rate risk is an important part of fixed-income investing. Bond prices and interest rates usually move in opposite directions.

When interest rates rise, prices of existing bonds may fall. When interest rates fall, prices of existing bonds may rise.

WAM helps investors understand how much a portfolio may react to interest rate changes.

A portfolio with a higher WAM may move more because it has more long-maturity bonds. A portfolio with a lower WAM may move less because its bonds mature sooner.

For example, a portfolio with a WAM of 6 months may not react much to interest rate changes. But a portfolio with a WAM of 6 years may show more price movement.

Still, WAM does not explain everything. It does not show credit risk, issuer quality or liquidity risk. Two portfolios may have the same WAM, but their risk can be very different.

One portfolio may hold highly rated bonds. Another may hold lower-rated bonds. Even if both have the same WAM, the risk will not be the same.

That is why WAM should be checked along with duration, credit rating, issuer profile, yield and liquidity.

WAM vs WALA vs Duration: Key Differences

WAM, WALA and duration may sound technical, but they are simple when explained in normal words.

WAM vs WALA can be understood like this. WAM looks ahead. It tells how much time is left before the bonds mature.

WALA looks back. It tells how old the loans already are. This term is mostly used for loan-backed securities.

Duration is different from both. It shows how much a bond or portfolio may move when interest rates change. So, duration is more about price movement.

In simple words, WAM vs WALA is about remaining maturity versus loan age. Duration is about interest rate sensitivity.

How To Use WAM When Choosing Bond/Debt Funds

WAM can be a useful number when choosing a debt fund or bond portfolio. It should not be the only factor, but it helps investors avoid looking only at returns.

Before choosing a fixed-income product, an investor can check whether the WAM matches their investment period.

If money is needed within one year, a very high WAM may not be suitable. If the money is needed after a few years, a medium or longer WAM may be reviewed.

The investor can also compare WAM with duration. If both WAM and duration are high, the portfolio may be more sensitive to interest rate changes.

Along with this, investors should also check the credit rating of the bonds, issuer strength, liquidity and yield.

WAM should be treated like a guide. It gives direction, but it does not give the full answer. A better fixed-income decision comes from checking all important details together.

Conclusion

Weighted Average Maturity is a simple and useful concept in fixed-income investing. It helps investors understand the average time left for bonds in a portfolio to mature after considering the size of each holding.

A higher WAM usually means the portfolio has more long-term bonds. A lower WAM usually means the portfolio has more short-term bonds.

WAM can help investors compare debt funds, understand interest rate risk and match investments with financial goals. But it should not be used alone. It should be checked with duration, credit quality, yield, liquidity and the investor’s time period.

When investors understand WAM properly, fixed-income investing becomes easier to read, compare and understand.

FAQs

1. What is weighted average maturity (WAM)?

Weighted Average Maturity is the average time left for all bonds or debt securities in a portfolio to mature, after considering each bond’s share in the portfolio.

2. How is weighted average maturity calculated?

It is calculated by multiplying each bond’s portfolio weight by its remaining maturity and then adding all the results.

3. What does a higher weighted average maturity mean?

A higher WAM means the portfolio has more long-term bonds. It may also mean higher sensitivity to interest rate changes.

4. What is the difference between WAM and WALA?

WAM shows the average remaining maturity of bonds. WALA shows the average age of loans in a pool.

5. How does WAM affect interest rate risk?

A higher WAM portfolio may react more when interest rates change. A lower WAM portfolio may show relatively lower price movement.

Disclaimer: Fixed returns do not constitute guaranteed or assured returns. Investments in corporate debt securities, municipal debt securities/securitised debt instruments are subject to credit risks, market risks and default risks including delay and/or default in payment. Read all the offer related documents carefully.