A group of Aetna shareholders is challenging the health insurer for donating to the American Action Network and the U.S. Chamber of Commerce — two organizations dedicated to undermining Obamacare.

Aetna donated over $7 million to the two groups during the Democrats’ effort to enact health care reform, though the contributions did not become public until this year, when the company accidentally “made the disclosure in a year-end regulatory filing with the National Association of Insurance Commissioners.”

In a latter to Aetna on Monday, the shareholders claim that the company did not comply with disclosure policies or inform its investors about the donations:

“We believe Aetna is not in compliance with its corporate political and lobbying disclosure policy, a policy which we negotiated and expected would be met in spirit and in letter,” read the Monday letter to Aetna CEO and President Mark Bertolini from Mercy Investment Services Inc. and the Sisters of Charity of Saint Elizabeth, two Catholic groups with investments in Aetna. [...]

But in their recent complaint to Aetna, the Catholic investors point to a 2007 letter of agreement in which Aetna promised shareholders that it would disclose all expenditures for lobbying and political purposes, as well as trade association payments and grass-roots spending. The Aetna policy followed a 2006 shareholder resolution calling for the company to disclose its political spending.

“We, investors, withdrew the resolution in good faith expecting that the resolution establishing oversight and transparency would be followed, revised as best practices evolved and in place for reference by the members of the committee preparing the annual reports,” read the letter. In an interview, Sister Valerie Heinonen, one of the letter’s authors, said investors were “dismayed” that the agreed-on policy had not been followed.

Aetna maintains that it intended the funds to be use for educational purposes, yet both the American Action Network and the Chamber are still fighting reform. Just days after the Supreme Court’s decision upholding the constitutionality of the law, AAN announced a $1.2 million advertising campaign urging Republicans to repeal the Affordable Care Act.