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Why diversify outside of the US?

The outperformance of US stocks in recent history has led some investors to question whether they should invest outside the US at all, yet there remains compelling reasons to diversify globally.

By Ben Bakkum

Quantitative Investing Associate, Betterment |

Published Sep. 21, 2022

Why diversify outside of the US? Sep 21, 2022 10:33:00 AM The outperformance of US stocks in recent history has led some investors to question whether they should invest outside the US at all, yet there remains compelling reasons to diversify globally. US investors often think of the S&P 500 Index (an index of the largest companies in the US by market capitalization) when referring to the performance of the stock market. This is not surprising to hear as most US based investors exhibit a “home bias”, where they focus their investing domestically and less on international. In a Vanguard 2020 study, households they surveyed had 81% of their portfolio allocations invested in the US. On top of that, US stocks have set a high bar for performance globally, outpacing the gains in stocks across Europe, Japan, and emerging markets over the last decade. It’s become natural to ask, “Can’t I get better returns just sticking with US stocks? Why would my Betterment portfolio have any allocation to companies outside of the US?” Currently, Betterment’s Core portfolio strategy in the 100% stock allocation has a target allocation of more than 40% in international equities. Below, this piece will cover reasons diversifying internationally makes sense, including: The global market portfolio is a starting point for asset allocation There’s no guarantee that US stocks will continue to outperform Diversification creates the potential for more consistent returns Investing in the global market portfolio The short answer is that Betterment constructs all of our portfolios to be representative of the makeup of global investable assets as a whole, and you’ll find that around 40% of the world’s equity assets are invested outside of the US. International investments play an important role in reducing the risk of concentration in any one particular country within your portfolio. There’s no guarantee of continued US outperformance We’ve all heard the phrase “past performance is not indicative of future results.” For instance, stocks of one region can string together multiple years of outperformance relative to others before that trend reverses and it enters a period of underperformance. The chart below illustrates this tug of war between US and international developed stocks. While the outperformance experienced by US stocks over the last decade is striking, international developed stocks dominated in the wake of the dot com bubble in the decade before that. “International stocks” is represented by the MSCI EAFE Index. “US stocks” is represented by the MSCI US Index. Past performance is not indicative of future results. You cannot invest directly in the index. Going back further into history, in the ‘80s international developed stocks actually outperformed US stocks to the same extent that US stocks have outperformed since 2009. We believe, and many on Wall Street will admit, that trying to time these cycles can be extremely difficult and a more consistent return may be achieved by holding exposure to each geographical region’s stocks over the long-term. Before US stocks’ strong run in recent history, investors may have been tempted to allocate more to emerging market stocks based on their momentum during the 2000s. Emerging market stocks had higher returns than US equities in eight of the ten years before 2011. If an investor piled into emerging market stocks in 2011 because of their decade long track record of outperformance, they would have largely missed out on the strong gains in the US over the following 10 years. There also may be reason to believe that markets outside the US have the potential to post strong gains over the next decade. Based on certain valuation metrics, US stocks appear more expensive than their global peers. For example, companies in places such as emerging markets source much of their revenue from quickly growing economies, which may enhance profitability in the future. Diversification helps avoid drawdowns and creates the potential for consistent returns International markets are not perfectly correlated with the US, meaning they do not move in lockstep. Allocating to markets around the world therefore promotes diversification, helping buffer portfolios from the heightened volatility of individual markets. The chart below ranks the returns of Betterment’s tenured Core portfolio strategy against different regions and asset classes across calendar years, illustrating diversification in action. The Core portfolio, with a 90% allocation to stocks and 10% allocation to bonds, consistently avoided losses compared to the poorest performing assets of recent history. This was also evident in 2020 where diversification provided downside protection as the US fell into a short recession and battled a pandemic. Investors focused on using the S&P 500 Index to benchmark performance will highlight that the index outperformed our Core portfolio in the time periods displayed. And while the strength of the US market is undeniable, it is important to not overlook the fact that our Core portfolio still has a sizable allocation to the US. Having a strategic, well-diversified portfolio allows investors to obtain exposure to not only markets that outperform like the US, but also to international stock markets and other asset classes that can dampen the downside in years where US stocks underperform. S&P 500” (US Large Caps) is represented by the S&P 500 Index. “EM” (emerging markets) is represented by the MSCI Emerging Markets Index. “US Small Caps” is represented by the Russell 2000 Index. “EAFE” (international developed markets) is represented by the MSCI EAFE Index. “US REITs” is represented by the MSCI US REIT Index. “US High Yield” is represented by the Bloomberg US Corporate High Yield Index. “Global Agg bonds” is represented by the Bloomberg Barclays Global Aggregate Bond Index. “Commodities” is represented by the Bloomberg Commodity Index. “BMT Core 90/10” represents the Betterment Core Portfolio strategy in the 90% stocks/ 10% bonds taxable allocation. Performance information for the Betterment allocation is based on the time-weighted returns of Betterment taxable portfolios with primary tickers that are at the target allocation every market day (this assumes portfolios are rebalanced daily at market closing prices). Dividends are assumed to be reinvested in the fund from which the dividend was distributed. Betterment allocations reflect portfolio holdings as of periods stated and include an annual 0.25% management fee. This does not include deposits or withdrawals over the performance period. These allocations are not representative of the performance of any actual Betterment account and actual client experience may vary because of factors including, individual deposits and withdrawals, secondary tickers associated with tax loss harvesting, allowed portfolio drift, transactions that do not occur at close of day prices, and differences in holdings between IRA and taxable portfolios. Investing in securities involves risks, and there is always the potential of losing money when you invest in securities. Market conditions can and will impact performance. Past performance is not indicative of future results. Market performance information is based on the returns of indexes tracked by Betterment, using returns data from sources and time periods listed. Performance is provided for illustrative purposes to represent broad market returns for asset classes that may not be used in all Betterment portfolios. The asset class performance is not attributable to any actual Betterment portfolio nor does it reflect any specific Betterment performance. As such, it is not net of any management fees. The performance of specific funds used for each asset class in the Betterment portfolio will differ from the performance of the broad market index returns reflected here. Past performance is not indicative of future results. You cannot invest directly in the index. At Betterment, we build portfolios and provide advice on portfolio allocations that should be suitable for each investor’s risk tolerance to help them reach their investment goals. Diversifying across stock markets, whether in the US or elsewhere in the world, helps in that continuous effort. It may be tempting to chase the high returns that US stocks have posted in recent history, anticipating that the US equity market will continue to outperform, but investors should recognize that future outperformance is near impossible to predict and that they should position themselves for a wide range of possible outcomes accordingly. This is why as a foundation of Betterment’s portfolio construction process, we start with a diversified global market portfolio.

US investors often think of the S&P 500 Index (an index of the largest companies in the US by market capitalization) when referring to the performance of the stock market. This is not surprising to hear as most US based investors exhibit a “home bias”, where they focus their investing domestically and less on international. In a Vanguard 2020 study, households they surveyed had 81% of their portfolio allocations invested in the US.

On top of that, US stocks have set a high bar for performance globally, outpacing the gains in stocks across Europe, Japan, and emerging markets over the last decade. It’s become natural to ask, “Can’t I get better returns just sticking with US stocks? Why would my Betterment portfolio have any allocation to companies outside of the US?” Currently, Betterment’s Core portfolio strategy in the 100% stock allocation has a target allocation of more than 40% in international equities.

Below, this piece will cover reasons diversifying internationally makes sense, including:

The global market portfolio is a starting point for asset allocation
There’s no guarantee that US stocks will continue to outperform
Diversification creates the potential for more consistent returns

Investing in the global market portfolio

The short answer is that Betterment constructs all of our portfolios to be representative of the makeup of global investable assets as a whole, and you’ll find that around 40% of the world’s equity assets are invested outside of the US. International investments play an important role in reducing the risk of concentration in any one particular country within your portfolio.

There’s no guarantee of continued US outperformance

We’ve all heard the phrase “past performance is not indicative of future results.” For instance, stocks of one region can string together multiple years of outperformance relative to others before that trend reverses and it enters a period of underperformance. The chart below illustrates this tug of war between US and international developed stocks. While the outperformance experienced by US stocks over the last decade is striking, international developed stocks dominated in the wake of the dot com bubble in the decade before that.

“International stocks” is represented by the MSCI EAFE Index. “US stocks” is represented by the MSCI US Index. Past performance is not indicative of future results. You cannot invest directly in the index.

Going back further into history, in the ‘80s international developed stocks actually outperformed US stocks to the same extent that US stocks have outperformed since 2009. We believe, and many on Wall Street will admit, that trying to time these cycles can be extremely difficult and a more consistent return may be achieved by holding exposure to each geographical region’s stocks over the long-term.

Before US stocks’ strong run in recent history, investors may have been tempted to allocate more to emerging market stocks based on their momentum during the 2000s. Emerging market stocks had higher returns than US equities in eight of the ten years before 2011. If an investor piled into emerging market stocks in 2011 because of their decade long track record of outperformance, they would have largely missed out on the strong gains in the US over the following 10 years.

There also may be reason to believe that markets outside the US have the potential to post strong gains over the next decade. Based on certain valuation metrics, US stocks appear more expensive than their global peers. For example, companies in places such as emerging markets source much of their revenue from quickly growing economies, which may enhance profitability in the future.

Diversification helps avoid drawdowns and creates the potential for consistent returns

International markets are not perfectly correlated with the US, meaning they do not move in lockstep. Allocating to markets around the world therefore promotes diversification, helping buffer portfolios from the heightened volatility of individual markets.

The chart below ranks the returns of Betterment’s tenured Core portfolio strategy against different regions and asset classes across calendar years, illustrating diversification in action. The Core portfolio, with a 90% allocation to stocks and 10% allocation to bonds, consistently avoided losses compared to the poorest performing assets of recent history. This was also evident in 2020 where diversification provided downside protection as the US fell into a short recession and battled a pandemic.

Investors focused on using the S&P 500 Index to benchmark performance will highlight that the index outperformed our Core portfolio in the time periods displayed. And while the strength of the US market is undeniable, it is important to not overlook the fact that our Core portfolio still has a sizable allocation to the US. Having a strategic, well-diversified portfolio allows investors to obtain exposure to not only markets that outperform like the US, but also to international stock markets and other asset classes that can dampen the downside in years where US stocks underperform.

S&P 500” (US Large Caps) is represented by the S&P 500 Index. “EM” (emerging markets) is represented by the MSCI Emerging Markets Index. “US Small Caps” is represented by the Russell 2000 Index. “EAFE” (international developed markets) is represented by the MSCI EAFE Index. “US REITs” is represented by the MSCI US REIT Index. “US High Yield” is represented by the Bloomberg US Corporate High Yield Index. “Global Agg bonds” is represented by the Bloomberg Barclays Global Aggregate Bond Index. “Commodities” is represented by the Bloomberg Commodity Index. “BMT Core 90/10” represents the Betterment Core Portfolio strategy in the 90% stocks/ 10% bonds taxable allocation.

Performance information for the Betterment allocation is based on the time-weighted returns of Betterment taxable portfolios with primary tickers that are at the target allocation every market day (this assumes portfolios are rebalanced daily at market closing prices). Dividends are assumed to be reinvested in the fund from which the dividend was distributed. Betterment allocations reflect portfolio holdings as of periods stated and include an annual 0.25% management fee. This does not include deposits or withdrawals over the performance period. These allocations are not representative of the performance of any actual Betterment account and actual client experience may vary because of factors including, individual deposits and withdrawals, secondary tickers associated with tax loss harvesting, allowed portfolio drift, transactions that do not occur at close of day prices, and differences in holdings between IRA and taxable portfolios. Investing in securities involves risks, and there is always the potential of losing money when you invest in securities. Market conditions can and will impact performance. Past performance is not indicative of future results.

Market performance information is based on the returns of indexes tracked by Betterment, using returns data from sources and time periods listed. Performance is provided for illustrative purposes to represent broad market returns for asset classes that may not be used in all Betterment portfolios. The asset class performance is not attributable to any actual Betterment portfolio nor does it reflect any specific Betterment performance. As such, it is not net of any management fees. The performance of specific funds used for each asset class in the Betterment portfolio will differ from the performance of the broad market index returns reflected here. Past performance is not indicative of future results. You cannot invest directly in the index.

At Betterment, we build portfolios and provide advice on portfolio allocations that should be suitable for each investor’s risk tolerance to help them reach their investment goals. Diversifying across stock markets, whether in the US or elsewhere in the world, helps in that continuous effort. It may be tempting to chase the high returns that US stocks have posted in recent history, anticipating that the US equity market will continue to outperform, but investors should recognize that future outperformance is near impossible to predict and that they should position themselves for a wide range of possible outcomes accordingly. This is why as a foundation of Betterment’s portfolio construction process, we start with a diversified global market portfolio.