German reinsurer Hannover Re on Wednesday became the third major company to leave a global climate alliance focused on reducing emissions that has faced growing political pressure in the United States.

Hannover said in an emailed statement that it was leaving the Net-Zero Insurance Alliance “after careful consideration,” without giving details.

“Regardless of this, Hannover Re remains committed to its sustainability strategy, the associated goals and its support for the Paris Agreement, and aims to achieve full climate neutrality by 2050 at the latest,” it added.

The move to leave the NZIA, part of the Glasgow Financial Alliance for Net Zero set up by U.N. climate envoy Mark Carney, follows the exit of founding members Munich Re at the end of March and Zurich Insurance earlier in April.

While Zurich had said it was leaving to focus on helping customers in the transition to a low-carbon economy, Munich Re said it was leaving because of anti-trust concerns.

The charge that companies in such climate alliances could be guilty of breaking anti-trust laws has been increasingly leveled by Republican politicians in some U.S. states as part of a pushback against sustainability efforts.

(Reporting by Tom Sims and Simon Jessop, Editing by Helen Reid, Kirsten Donovan)