A FINRA Investor Education Foundation study of retail investors last March found only 9% of respondents held ESG investments. This is despite 57% of them saying they thought ESG investing can lead to positive change in the world. A big factor behind this gap is retail investors' lack of familiarity or knowledge about ESG products, the study found.

Neil Bathon, managing partner of funds researcher FUSE Research Network, said obscure and inconsistent ESG ratings also make it hard for individuals to understand the value of ESG investing, especially after a fall-off in tech stocks and rising oil prices last year hurt returns in ESG funds. For many individuals, "it's very difficult to trace investment to impact" on environmental or social matters, Bathon said.

Vanguard's NZAM participation was modest to begin with. It said 4% of its assets would be aligned by 2030 with a goal of net-zero emissions, compared with State Street committing 14% of its assets. BlackRock has said it expects more than half its assets to meet the 2030 target, but it has not made a firm commitment. "You wonder why Vanguard signed up in the first place," said Hortense Bioy, global director of sustainability research at fund ratings firm Morningstar Inc. Vanguard representatives said the company looks forward to continuing constructive conversations with policymakers. A BlackRock spokesperson said it "has a large and diverse client base with a range of investment goals" and that as a fiduciary, "our only agenda is delivering the best financial results." State Street declined to comment. ESG BACKLASH Kirsten Spalding, vice president at sustainability nonprofit Ceres, a founding partner of NZAM, said she believed that Vanguard's move was mainly in response to a backlash against ESG from Republican politicians. Vanguard's NZAM withdrawal spared it from appearing at a Dec. 15 Texas hearing where BlackRock and State Street executives were grilled about their participation in NZAM and other ESG initiatives. State Street Executive Vice President Lori Heinel said during the hearing the firm must do some "delicate threading" to account for a wide range of views held by clients globally.

Among the BlackRock and State Street institutional clients putting a higher priority on ESG would be European asset owners and big U.S. pension funds run by Democratic officials.

One is New York City Comptroller Brad Lander, who oversees some $41 billion of city assets managed by BlackRock, $31 billion managed by State Street, and none by Vanguard. "We have made this commitment to net zero carbon and we can't achieve it unless our asset managers are aligned with it," Lander said. Vanguard's exit from NZAM has not fully spared it from the ESG backlash. A coalition of 13 Republican state attorneys general are pressing on with a motion asking federal energy regulators to limit Vanguard's ability to invest in public utilities.

Representatives of several attorneys general declined to comment on what impact Vanguard's NZAM departure may have on the motion.

(Reporting by Ross Kerber in Boston and Tommy Wilkes in London; Additional reporting by Simon Jessop in London; Editing by Greg Roumeliotis and Matthew Lewis)

By Ross Kerber and Tommy Wilkes