Portfolio Diversification: Tougher Than It Used to Be?

Editorial Team
7 Min Read


“One of the crucial vexing issues in funding administration is that diversification appears to vanish when buyers want it probably the most.” — Sébastien Web page , CFA, and Robert A. Panariello, CFA, “When Diversification Fails”

Two improvements during the last half century have vastly expanded the vary of securities to which buyers have entry.

Mutual funds had been first launched en masse to the retail investing public within the Seventies, and now tens of hundreds have been created and bought to buyers. Starting within the Nineteen Nineties, an identical wave of exchange-traded funds (ETFs) adopted of their wake.

As mutual funds and ETFs have multiplied, far-off locales have develop into investable with the press of some buttons. Rising market fairness funds led to frontier market fairness funds and so forth.

In principle, ever-greater entry to world fairness markets ought to have made it simpler for buyers to construct and harvest the advantages of diversified world inventory portfolios.

However has it actually? Has diversifying throughout world fairness indices truly helped cut back portfolio danger?

To seek out out, we collected as a lot information as we may discover from numerous world inventory market indices going again over the previous a number of a long time: the S&P 500 in the USA; the FTSE 250 in the UK; the DAX in Germany; the CAC 40 in France; the Nikkei in Japan; the Cling Seng in Hong Kong, SAR; the SSE in mainland China; the TSX in Canada; the BVP in Brazil; the RTS in Russia; the KOSPI in South Korea; the SNX in India; the AOR in Australia; and the IPC in Mexico.

With this information in hand, we examined the correlations amongst every two-index mixture within the Nineteen Eighties, Nineteen Nineties, 2000s, and 2010s to see whether or not diversifying between them truly yielded the hoped-for benefits by way of danger discount and the way these benefits might need modified over time.

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Within the Nineteen Eighties, the typical correlation coefficient amongst all of the indices studied for which we had information was 0.25. The minimal correlation coefficient was –0.51, for the BVP and HSI, whereas the utmost, for the S&P 500 and the FTSE 250, was 0.83. Of the 45 correlation coefficients in our pattern for the last decade, 8 had been adverse.


Correlations amongst International Inventory Indices: Nineteen Eighties

Chart showing Correlations among Global Stock Indices: 1980s

Quick ahead to the Nineteen Nineties and the 2000s, and the adverse correlations petered out as dispersion among the many indices fell dramatically together with the related diversification advantages.


Correlations amongst International Inventory Indices: Nineteen Nineties

Chart showing Correlations among Global Stock Indices: 1990s

Correlations amongst International Inventory Indices: 2000s

Chart showing Correlations among Global Stock Indices: 2000s

Within the Nineteen Nineties, the typical correlation coefficient had already risen to 0.30. Of the 91 correlation coefficients, solely 7 had been adverse. By the 2000s, the typical coefficient had climbed to 0.59 and there wasn’t a single adverse correlation among the many 91 index mixtures.

This development continued into the 2010s and the 2020s. Between 2020 and 28 February 2022, the typical correlation was 0.70 and the minimal, for the RTS and SSE combo, was 0.37. So, for buyers trying to cut back volatility this decade, dividing their fairness allocation amongst worldwide inventory indices has not been a very efficient technique.


Correlations amongst International Inventory Indices: 2010s

Chart of Correlations among Global Stock Indices 2010s

What occurred? Markets all over the world have developed, and globalization has been the important thing theme of that course of. In an interconnected and built-in world, fairness markets have grown more and more correlated.

So, whilst buyers have larger entry to distant frontier markets in addition to all method of developed and growing inventory indices, the advantages of diversifying their fairness allocations amongst them has diminished.


Correlation amongst World Indices

Min. Max. Median Imply Std. Dev.
Nineteen Eighties -0.51 0.83 0.25 0.25 0.32
Nineteen Nineties -0.12 0.83 0.30 0.31 0.24
2000s 0.20 0.95 0.62 0.59 0.16
2010s 0.19 0.87 0.50 0.51 0.14
2020s 0.37 0.93 0.72 0.70 0.14

Within the Nineteen Eighties, an investor may diversify throughout the HSI and the BVI and minimize the related portfolio volatility by 12 share factors in contrast with historic volatility. 

But, within the 2020s up to now, the optimum index combo allocation for diversification functions yields that paltry 0.36 correlation coefficient. That solely cuts portfolio volatility by 3 share factors in contrast with historic volatility and requires an allocation to Russian equities, which have many strikes in opposition to them nowadays.

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After all, whether or not this development of accelerating inventory index correlation will proceed is an open query. Given the current shake-up in world affairs, the reply might very nicely be no.

Many have speculated that the globalization wave of the final half century has crested and is starting to recede. In such a situation, world inventory market indices may develop into much less correlated and their efficiency more and more decoupled from each other. Whether or not that finally ends up being the case might be one thing to keep watch over within the months and years forward.

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All posts are the opinion of the writer. As such, they shouldn’t be construed as funding recommendation, nor do the opinions expressed essentially replicate the views of CFA Institute or the writer’s employer.

Picture credit score: ©Getty Pictures / Yuichiro Chino


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