Anyone within the industry must have inevitably heard about the risk-reward trade-off or risk-adjusted returns. Understanding and managing portfolio and investment risks within an investor’s basket of investments is paramount in ensuring returns commensurate with the risks being undertaken. One of the crucial factors within portfolio risk management is grasping the concept of diversification, and the correlation of returns between underlying securities.

Balancing risk and expected return is burdensome for any investor considering any array of investment choices and decisions. Portfolio diversification could in essence reduce risk; the lower the correlation between returns from different securities in a portfolio, the greater is the added benefit from the diversification within a portfolio.

The importance of viewing a portfolio of investments in its totality rather than focusing on individual holdings is vital. Since diversification can help reduce risk without affecting the portfolio’s expected return, an important consideration an investor must make is the assessment of assets and their contribution to the risk and return of the overall portfolio.

An American economist most famous for his work in Modern Portfolio Theory, Harry Markowtiz, concluded that “portfolio risk is reduced by diversifying across assets as long as the returns of combined risky assets are not perfectly positively correlated.” The findings from his study conclude that it is difficult to find equities that are consistently uncorrelated as the large majority of the components generally display some degree of positive correlation, despite forming part of different sectors.

“Do no put all your eggs in the same basket,” which means not to invest entirely in one asset class, such as a 100% exposure to bonds, or 100% exposure to equities. It thus follows that in order to diversify further, other asset classes need to be considered. It has been statistically proven that diversification (spreading investments across more than one asset class) reduce overall portfolio risk due to the non-linear correlations between asset classes. However, it is worth mentioning that correlations are extremely dynamic and correlation of returns between asset classes can vary from time to time.

Correlations between various assets across a portfolio have a direct impact on the level of diversification (and risk) of any portfolio; the less correlated the investments, the lower the risk of the portfolio. Having said this, while correlations between a portfolio’s assets are crucial to diversification, there are other important factors which can also impact portfolio diversification as well as the different weights for the different assets within a given portfolio.

Asset and Investment Managers around the world, whose job is to run and manage mutual funds (or collective investment schemes) of differing sizes of varying themes view the concept of portfolio diversification and the correlation of returns within a context of a portfolio (or fund) as pivotal and a fundamental part of their risk management process. It is hence the job of Fund Managers to constantly review the inherent risks within a fund, and ensure that the expected return of a fund is commensurate with the risk being undertaken and continuously monitor such correlations in order to achieve the best results possible. This is a highly complex process, and this is why a large number of investors worldwide prefer to invest in collective investment schemes (rather than in direct securities) as they offer an investor a diversified exposure to the markets, whose risk is being managed on an ongoing basis, and which risk management process is delegated to asset managers.