Why Sustainable Investing Strategies Are Doing Better Than You Might Think

Key Takeaways

• Sustainability-focused indexes have nearly kept pace with—or even outperformed—the broader US stock market so far in 2026.
• Semiconductor stocks drove gains, keeping ESG indexes relatively in line with the broader market, despite characteristic underweights to energy stocks.
• Software stocks detracted from the performance of sustainable strategies, while key AI infrastructure companies Monolithic Power and Micron contributed with their energy-efficient power solutions.

Big-name software stocks have struggled this year, while energy stocks have soared. This may sound like a recipe for significant underperformance in sustainable investing strategies, which tend to own many tech and few or no energy names. Instead, while some ESG indexes are lagging in 2026, the gap isn’t as wide as investors might expect.

The Morningstar US Sustainability Index has gained 4.3% this year through April 24, not far behind the 5.2% return on the broader stock market as measured by the Morningstar US Market Index.

Across strategies focused on environmental, social, and governance metrics, there’s been a wide range of returns. The Morningstar Developed Markets Sustainable Activities Involvement Index, which includes companies with at least 50% of revenues from products and services aligned with UN Sustainable Development Goals, is up more than 16%. The Morningstar Developed Markets Paris Aligned Benchmark, which is designed to resemble the broad US equity market while following a decarbonization trajectory, is up about 3.7%.

Conditions are challenging for sustainable investing. The Iran war set off a massive rally in oil prices, leading the Morningstar US Energy Index to rise 28.03% through April 24. At the same time, many technology stocks have struggled, as investors have had second thoughts about the impact artificial intelligence could have on long-held competitive advantages, especially among software companies. The Morningstar US Technology Index rose 7.98% in 2026 through April 24, having recovered from significant losses through the end of March.

Tech and Energy Exposures Drive Performance Dispersion

As a group, ESG screens often avoid the energy sector, which is filled with oil and gas names, which are seen as contrary to strategies that invest in companies that don’t harm the environment. Instead, many ESG strategies tend to carry above-market concentrations in sectors such as healthcare and financial services.

But when it comes to driving performance, above-market allocations to tech stocks have been more critical. While relative weightings have gone down slightly alongside the boom in AI infrastructure buildouts, there’s still a lot of tech to be found within ESG. At the end of 2021, 27.7% of the US Sustainability Index’s portfolio was made up of technology stocks—including Nvidia NVDA, Microsoft MSFT, and Cisco Systems CSCO—a full percentage point above the US Market Index’s 26.6% concentration. Today, tech stocks are 30.39% of the US Sustainability Index and 32.08% of the US Market Index.

At the other end of the spectrum, environmental considerations sharply limit exposure to energy companies. The US Sustainability Index has a 2.83% weighting in energy stocks, the Developed Markets Sustainable Activities Index has none, and the Developed Markets Paris Aligned Benchmark registers a 0.10% weighting. Even the overall market has little exposure to energy stocks; the US Market Index has a 4.08% weighting to the sector.

“Sustainable funds generally underperform when energy drives the market,” says Alyssa Stankiewicz, associate director of parent research at Morningstar. In 2022, when Russia’s invasion of Ukraine drove up energy prices, the US Sustainability Index had its worst performance since its inception in 2016.

Energy stocks have had little overall impact on the US Sustainability Index’s performance this year, thanks to the sector’s small weight. Energy contributed 0.67 percentage points to the index’s 4.30% return, not far from the 0.80 percentage points the US Market Index gained from the sector. Instead, big tech stocks (excluding software) helped sustainability strategies keep pace with the broader market.

AI Infrastructure and Big Tech Drove Sustainable Investing Strategies’ Performance

So far in 2026, tech stocks have contributed 2.42 percentage points to the US Sustainability Index’s 4.30% gain. Three of the index’s top five stocks are semiconductor companies: Nvidia, Advanced Micro Devices AMD, and Applied Materials AMAT. Amazon AMZN, which falls into the consumer cyclical sector, was the second-largest contributor to the index’s returns. AMD is up 62.41% this year through April 24. Nvidia rose 11.68%, though the index has over eight times more exposure to that stock—10.38% versus 1.27% for AMD.

The double-digit gain on the Developed Markets Sustainable Activities Involvement Index is also notable. “This index selects companies based on what they produce, rather than how they currently operate, including those better positioned to capture the upside of the AI investment cycle, though this can come with the trade-off of concentration risk with outsized growth relative to the other companies in the index,” explains Margaret Stafford, director of product management for index products at Morningstar.

The index’s 16.17% year-to-date return was fueled by Micron Technology’s MU 74.12% return, which contributed 6.18 percentage points to the gain. Micron, which makes up 11.38% of the index’s total weight, “is included in the index because more than 50% of its revenues are linked to low‑carbon, energy‑efficient technologies. It has benefitted tremendously from AI infrastructure demand and experienced significant earnings growth,” Stafford says.

Another winner for the strategy was Monolithic Power Systems MPWR, which has gained 80.4% this year. The company gets nearly all its revenues from energy‑efficient power solutions, according to Stafford.

However, it wasn’t all good news on the tech front. Microsoft was the largest detractor in the US Sustainability Index, subtracting 1.01 percentage points as its second-highest-weighted stock with a 12.01% loss as of April 24. The second-largest detractor, Intuit INTU, subtracted 0.26 points from the index while posting a loss of 39.86%. The index’s overweighting in the financial services and healthcare sectors also detracted.