Funds that invest sustainably love tech companies – and Alphabet in particular.

MSCI studied the year end 2020 holdings of the 20 largest funds that invest based on environmental, social and governance considerations. These funds account for about 13% of total assets in ESG equity funds. They include active and index-based strategies.

The information technology sector of the S&P 500 accounted for the largest allocation in most funds, according to MSCI's analysis. Funds' holdings in these stocks ranged from 3.5% of their assets to more than 37%.

Most of the ESG funds in the study had well over 20% of their assets in IT.

Meanwhile, energy stocks accounted for a minimal portion of the funds' holdings. This helped the ESG funds outperform last year, as tech rallied while energy declined.

Indeed, Google's parent company was held in 12 of the funds — making it the most widely held stock among the participants — with an average weight of 1.9% at year end, according to the study.