Diversification: Capturing Those Outliers

 | May 17, 2017 12:51

Originally published by BetaShares

At a conceptual level, diversification is all about spreading risk and not putting all our eggs in one basket. Quantitatively, as I’ve previously explained, one of the main benefits of diversification is lowering the volatility for a given level of expected return. However, another way of looking at it is that diversification also allows us to improve our returns for a given level of risk, either through levering up to our desired risk tolerance or by capturing positive outliers in the return distribution of stocks in the market.

Both here and abroad, a concentration of stock returns has often driven overall market performance, in that a relatively small number of large-cap ‘winners’ can carry an entire index. One key implication is there is potentially a very large opportunity cost of not holding the index or a broad market portfolio (particularly in a bull market), either through attempts at stock picking or trying to diversify using only a few stocks. By constructing your core portfolio using a limited number of securities, you are potentially leaving significant returns on the table by not broadening your exposure.

Much has been written about the underperformance of most active managers against their respective benchmarks, and one possible reason is the degree of outperformance by a relatively small number of stocks. These positive outliers may not have been held or have been held underweight by underperforming active managers, dragging down overall fund returns relative to the index. To investigate the degree that a small number of stocks drive index performance, let’s decompose the returns in the S&P/ASX 200 Index over the past few years and find out which stocks were the key drivers of index performance during broad market rallies.

S&P/ASX 200 Total Return Attribution