<span class="hpt_headertitle">8 factor framework for analysing any debt mutual fund</span>

8 factor framework for analysing any debt mutual fund

Just in case you are new to this blog (which most probably you will be :)), you can read the first part of this series here Link

Debt Fund Returns
Interest from underlying debt securities
Price changes in the market value of underlying debt securities
(based on interest rate changes)

or in other words..

Debt Fund Returns everyday = (Yield to maturity/365) + (-1*Modified duration*
% change in YTM)

8 factor framework for investing in any debt mutual fund

  1. Yield to Maturity – Expense Ratio
  2. Credit Quality: % of government, AAA and AA rated bonds
  3. Modified Duration
  4. Average Maturity
  5. Size
  6. Exit Load
  7. Historical NAV movement graph
  8. Returns

1.Yield to Maturity – Expense ratio
This will approximately be equal to the returns that you can expect from the fund in a year if there is no change in the interest rates (read as yield to maturity)

2.Credit Quality: % of government and AAA rated bonds
This is to check if the fund is taking any credit risk. The higher the % of AAA and government securities in the portfolio of debt mutual fund, lower is the credit risk i.e probability of default or downgrade in the fundEven AA papers are fine to a certain extent.

A debt fund which is taking credit risk will have a higher yield to maturity(because when you are lending to a lower rated borrower you would demand a higher interest rate). So the Yield to maturity level compared to other funds can also be used as a proxy to find out if the fund is taking credit risk.


I personally prefer funds which do not take credit risk and have a high % portfolio allocation in either government bonds or AAA securities.

3. Modified Duration
Check this number to figure out if the fund is undertaking any interest rate risk. Higher the modified duration higher is the interest rate risk i.e sensitivity to interest rate changes. Also check if the modified duration will be actively managed i.e will the fund manager regularly adjust the modified duration based on his interest rate view. If the fund is actively managed then the fund manager will typically try to increase duration if he expects interest rates to fall and vice versa.

4.Average Maturity 
This no in my personal opinion is not too important but provides you a sense of tenor of the debt securities that the fund holds. The lower the tenor the lower is the interest rate risk. Few also interpret this number (some also use modified duration) as an approximate indicator of the time for which an investor must typically be invested in the fund. It is also used to ascertain the category of the fund. (Liquid, Ultra Short Term, Short Term, Income – in increasing order of average maturity)

Fund size is important as flows are normally of a significant size (because corporate companies are major investors in debt funds). Further, trading in the debt market requires huge minimum lots. A reasonably sized debt fund helps the fund manager to meet redemptions (read as investors taking money out of the fund) without resorting to distress sales and also provides sufficient size to trade in debt securities. Personally, I would be comfortable with a fund that has a size more than INR 500 cr at least.


6.Exit LoadAn Exit Load is the fee charged by mutual funds if an investor wishes to withdraw his investment in mutual fund within a specified period from that fund. This charge is calculated as a percentage of the NAV and not on the amount you invest. The lower the exit load period the better!!

7.Historical NAV movement graph
Provides you a sense of the historical volatility in the returns of the fund.

8. Returns
Also just have a look at the fund’s historical returns and its performance vis-a-vis the peer group. We typically need a fund which has performed over a long period and most importantly has done it consistently.

Enough of theory, let’s take the example of a few funds and apply the framework..

I will be using value research online (link) and morningstar website (link) for all my analysis

Example 1: HDFC Liquid Fund – Growth

1.YTM – Expense Ratio

= 7.28%-0.41% = 6.87%

So 6.87% is the annual return to be expected from the fund if the YTM remains the same. Expense ratio seems reasonable.

Daily stable return portion = 6.87%/365 =0.019% every day gets added to the NAV

i.e for every Rs 1 lakh invested Rs 19 will get added everyday

2.Credit Quality 

As seen above ~98.5% of the underlying debt securities are in AAA bond securities. Hence the fund is not taking any credit risk to improve performance.

But, the fact that the fund is not taking any credit risk right now does not mean that it won’t take any credit risk in the future. So let us also check its historical credit quality for getting a better idea.

As seen above the fund has historically maintained above 98% in AAA bond securities for the last 5 years and therefore we can reasonably conclude that the fund does not take credit risk.

3. Modified Duration

The modified duration is 0.14 years. This implies that if the interest rates (read as YTM) goes down by 1% (i.e from 7.28% to 6.28%) then the NAV will increase by 0.14% and if instead the interest rates goes up by 1% then the NAV will reduce by 0.14%. Thus as seen, the impact due to interest rate changes are minimal as the fund has low modified duration.This also implies that the fund has not undertaken any interest rate risk to improve returns.

4.Average Maturity

The average maturity is 0.14 i.e 0.14*365 which is around 51 days. This will also help us ascertain the category of fund (but let us leave that for the next post).


The size is at Rs 30,622 cr and is comfortably above our threshold of Rs 500 cr.

Exit Load

There is no exit load for the fund which is good.

7.Historical NAV Graph

From our analysis so far, we know that the fund does not take credit risk and interest rate risk. Hence the returns must be pretty stable as it is only driven by the interest income which is the YTM (Yield to maturity) component. We can confirm that from the above 10 year NAV movement chart of the fund which shows extremely smooth movement in NAVs.

8.Historical Returns

You can check them from the above chart. As seen, the fund has consistently outperformed its category average in all the years.

Final thoughts:

Thus if I were to invest in the fund I will expect approximately around 6.87% returns from the fund provided interest rates stay around the same levels. If interest rates go down then my returns will also go down (as the YTM component goes down and so does your daily return i.e YTM/365) and if instead the interest rates go up then my returns will also correspondingly improve. (Note: Since modified duration is very low I am not taking into account the underlying debt security price changes due to interest rate movement.)

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