By Ross Kerber

A group of 15 Republican state attorneys general have questioned whether directors of BlackRock mutual funds are sufficiently independent of the world's largest asset manager.

In a letter dated July 6 and provided to Reuters on Friday by a representative of Montana Attorney General Austin Knudsen, the group reviewed longstanding concerns about mutual fund governance in the context of the officials' more recent efforts to limit the growing consideration of environmental, social and governance (ESG) factors by companies and investors.

BlackRock did not immediately comment.

The letter was addressed to ten individuals listed in a BlackRock filing as nominees to a board that oversees BlackRock closed-end mutual funds.

The AGs sought information on things such as financial relationships that they wrote "could undermine director independence."

Among other things, they said BlackRock fund trustees who serve as directors of companies where BlackRock owns more than 5% of shares could lead to independence concerns. They also cite how BlackRock fund directors are responsible for dozens of funds - exceeding BlackRock's own "overboarding" guideline for public company boards.

Critics have raised similar issues in the past about whether well-paid mutual fund directors are positioned to speak up. The attorney generals apply that concern in the context of stances BlackRock has taken on ESG issues, such as a request for portfolio companies to account for climate change.

"It strains credulity that a director of a mutual fund would not feel pressure against standing up to BlackRock’s ESG agenda—even when it is not in the financial interests of the fund’s shareholders," they wrote.

Republican state attorneys general previously have questioned how top asset managers cast proxy votes at corporate annual meetings, and demanded information about how they seek to tackle climate change.

(Reporting by Ross Kerber; editing by Diane Craft)