The Hidden Hazard in Climate Portfolios: Equity Concentration Risk

Investors seeking to reduce climate risk in targeted equity strategies might not be aware of hidden hazards to portfolio construction. Climate-focused benchmarks have big positions in US heavyweight stocks, which adds concentration risk and mutes portfolio diversification benefits.

There are different ways for equity portfolios to address climate-related issues. Some might focus on companies that help solve climate challenges, while others target firms with lower carbon emissions than their peers. Another approach is to focus on companies that are integral to the energy transition across diverse sectors and industries.

Whatever approach an investor chooses, we believe it’s important to manage a climate-related portfolio with the same research rigor and risk management as any other active equity strategy. That means ensuring that the portfolio has adequate diversification.

Heavy Weights in US Mega-Caps

Passive approaches to climate-focused investing may lack that diversification. That’s because key climate benchmarks are prone to heavy concentration in a small group of giant US stocks—just like broad cap-weighted benchmarks.

It sounds surprising. After all, you would expect a climate-focused benchmark to have much different positions than the broad equity market. But in fact, the MSCI World Climate Paris Aligned Index is heavily concentrated in the same stocks that dominate the MSCI World broad market index. This is largely by design, as climate indices typically seek to limit tracking error to the broader market index.

As a result, the weight of the 10 largest stocks in the MSCI World Climate Paris Aligned Index has more than doubled since 2017, to 26% (Display), higher than their weight in the MSCI World. Most of the 10 biggest stocks in the MSCI World Climate benchmark are the same as those in the MSCI World and S&P 500, such as NVIDIA, Apple and Microsoft. And the top 10 account for 33.5% of the MSCI World Climate Paris Aligned Index risk, versus 31.4% of the MSCI World risk.

Key Climate Benchmark Has Large Weights in Giant US Stocks