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Wednesday, April 18, 2007

Diversification - Take 2

Rohit Sharma in his comment to my post on diversification did not agree with my rational.
"HDFC prudence, not being an index fund, would be investing in much more risky stocks."
He goes on to add:
"One must take into consideration the Risk involved in the so called 'diversification'.
HDFC prudence has given better results by taking Higher Risks. I don’t think there is any thing novel in that. It is almost a Tautology"
And finally:
"'Diversification', as you define in this article’, seems to be inconsistent with 'Diversification' that the investing world generally believes in i.e. picking up funds to minimize risks and not maximize profits."
I generally agree with his rationale but have some reservations. First HDFC Prudence is a hybrid fund. Therefore, by definition a portion of its portfolio is invested in Debt / Bond markets which are inherently less risky than stock. Therefore, the fund could have some of the stocks which were more risky than Sensex but overall its portfolio would be less risky. This is somewhat indicated by the fact that it had very little down years.

Second, I do agree with the fact that diversification is generally done to avoid risk. However, unlike him, I believe diversification can also give rise to higher returns (for the same risk taken). This can happen when the portfolio is made up of negatively co-related instruments i.e. when one goes up the other goes down. This is what the efficient frontier in portfolio theory is all about. The following excerpt is from the moneychimp explains it clearly
The second important property of the efficient frontier is that it's curved, not straight. This is actually significant -- in fact, it's the key to how diversification lets you improve your reward-to-risk ratio. Combining securities lowers risk To see why, imagine a 50/50 allocation between just two securities. Assuming that the year-to-year performance of these two securities is not perfectly in sync -- that is, assuming that the great years and the lousy years for Security 1 don't correspond perfectly to the great years and lousy years for Security 2, but that their cycles are at least a little off -- then the standard deviation of the 50/50 allocation will be less than the average of the standard deviations of the two securities separately. Graphically, this stretches the possible allocations to the left of the straight line joining the two securities.

All said, I concur that lower risk and not higher returns is the primary reason for diversification. Also, practically, its very difficult to find negatively co-related securities.

I agree that looking only at HDFC Prudence is not the correct way to look at the virtues of diversification. The results confirm that for higher returns you need to take higher risk. But then they also give an historical indication of how the results in India have been.

However, what I intend to do in this post (as in previous post) is try to look at diversification in different instruments and not just diversification in stocks.

I will choose a simple portfolio made up of Sensex and Bank Deposits. I will invest a fixed amount of Rs 1000 at the begining of every year (no market timing). I will consider 5 different portfolio's of 100%, 70%, 50%, 30% and 0% stocks. For bank deposits I will consider 1 year returns. The results are:

100% Stocks
70% Stocks
50% Stocks
30% Stocks
0% Stocks
1991 85.80% 63.66% 48.90% 34.14% 12.00%
1992 33.62% 28.16% 23.99% 19.28% 11.00%
1993 27.82% 23.73% 20.51% 16.79% 10.00%
1994 14.26% 13.54% 12.97% 12.29% 11.00%
1995 -20.45% -13.16% -7.36% -0.59% 12.00%
1996 -0.93% 2.69% 5.15% 7.66% 11.50%
1997 18.16% 15.83% 14.33% 12.87% 10.75%
1998 -16.48% -8.53% -3.23% 2.07% 10.00%
1999 63.32% 43.98% 32.72% 22.54% 9.00%
2000 -23.75% -14.87% -8.53% -1.82% 9.00%
2001 -18.25% -9.21% -3.79% 1.20% 8.00%
2002 3.53% 4.18% 4.51% 4.79% 5.13%
2003 72.55% 45.35% 31.18% 19.28% 4.63%
2004 12.43% 10.40% 9.00% 7.58% 5.38%
2005 41.82% 31.99% 25.06% 17.80% 6.25%
2006 46.32% 37.41% 30.33% 22.04% 6.63%
Average 21.24% 17.20% 14.73% 12.37% 8.89%
StdDev 34.16% 23.39% 16.65%
10.06% 2.56%
Min Returns -23.75% -14.87% -8.53% -1.82% 4.63%

StdErr
8.54% 5.85% 4.16% 2.52% 0.64%

The % age returns for each year indicate by how much the total investment grew (shrunk) during that 1 year period.

The results are not surprising but give an indication of the historical returns of different portfolios. The risk (indicated by StdDev) and the return (indicated by Average) decreases as the %age of stock decreases.

We have to take the average stock market return with a pinch of salt. StdErr is a statistical figure that indicates how close my sample Average is to the real world i.e. by how much will the average vary if I take a different sample. Higher standard error indicates that Average (i.e. returns) may not remain the same in the future.

Now let's look at the results when I balance my portfolio at the beginning of every year i.e. while instead of dividing Rs 1000 every year in stocks and deposits. I add Rs 1000 to the previous year returns and divide the whole amount into stocks and deposits. The results are:

100% Stocks 70% Stocks 50% Stocks 30% Stocks 0% Stocks
1991 85.80% 63.66% 48.90% 34.14% 12.00%
1992 33.62% 26.83% 22.31% 17.79% 11.00%
1993 27.82% 22.47% 18.91% 15.35% 10.00%
1994 14.26% 13.28% 12.63% 11.98% 11.00%
1995 -20.45% -10.72% -4.23% 2.26% 12.00%
1996 -0.93% 2.80% 5.29% 7.77% 11.50%
1997 18.16% 15.94% 14.45% 12.97% 10.75%
1998 -16.48% -8.54% -3.24% 2.06% 10.00%
1999 63.32% 47.03% 36.16% 25.30% 9.00%
2000 -23.75% -13.93% -7.38% -0.83% 9.00%
2001 -18.25% -10.38% -5.13% 0.12% 8.00%
2002 3.53% 4.01% 4.33% 4.65% 5.13%
2003 72.55% 52.18% 38.59% 25.01% 4.63%
2004 12.43% 10.32% 8.91% 7.50% 5.38%
2005 41.82% 31.15% 24.04% 16.92% 6.25%
2006 46.32% 34.41% 26.47% 18.54% 6.63%
Average 21.24% 17.53% 15.06% 12.60% 8.89%
StdDev 34.16% 23.80% 16.92% 10.11% 2.56%
Min Returns -23.75% -13.93% -7.38% -0.83% 4.63%
StdErr 8.54% 5.95% 4.23% 2.53% 0.64%

Again pretty much similar results. One important observation is the minimum return in all cases is much less than what it would be without balancing.

Finally, have a look at the sheet to find the actual growth in the Rs value. Even though the diversification might reduce your overall returns it makes getting through the bad years a little easier. This makes a difference between your continuing to invest in the stock market or just getting out and not investing for quite some time thereby missing out on the best years.

Have a look at the Min Returns. Pick a portfolio (asset allocation) that matches with your risk profile. If you can withstand 20% loss in any given year (and still continue investing) then 100% diversified stocks is your ideal asset allocation. But if you cannot then you should diversify not only in stocks but in other instruments.

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