Dec 23 (Reuters) - The Republican-led U.S. House of

Representatives Judiciary Committee is seeking information from

some 60 U.S. asset managers about their involvement with an

investor climate group, adding pressure against environmental

efforts by large investors.

Letters sent on Friday to members of the Net Zero Asset

Managers initiative, or NZAM, were signed by committee Chairman

Jim Jordan and Representative Thomas Massie. They made claims in

line with a committee report released on Dec. 13 that

Republicans say showed fund firms colluded to cut emissions. The

committee's Democrats have dismissed such claims, and big fund

firms have denied similar charges.

Representatives for companies that received the letter

including BlackRock ( BLK ), State Street and JPMorgan

Asset Management did not immediately comment when

contacted late on Friday.

Republicans previously have taken credit for prompting those

three fund managers to step back from another investor group,

the Climate Action 100+.

NZAM says it is an international group with more than 325

signatories managing $57.5 trillion, according to its website.

Members pledge to support the goal of net zero greenhouse gas

emissions by 2050, using influence such as how they vote their

proxies at corporate meetings.

The letters from Jordan and Massie state that companies'

efforts with NZAM and the affiliated Glasgow Financial Alliance

for Net Zero "may violate U.S. antitrust law," citing the

earlier report. They ask for information such as how companies'

participation in NZAM changed their stewardship strategies.

Mindy Lubber, CEO of Boston-based environmental advocacy

group Ceres, an organizing partner of NZAM, said in an interview

that the letters were "consistent with other efforts to suggest

that investors ought not to consider climate risk, when of

course they should be aware of climate risk as part of their

fiduciary duty."