An anonymous donor gave $7 million to the American Action Network, a conservative advocacy group led by former Republican Minnesota U.S. Sen. Norm Coleman.
The donation accounts for more than 25 percent of the $27.5 million the organization raised between July 1, 2010, and June 30, 2011, according to tax returns the organization is filing with the Internal Revenue Service.
As a tax-exempt organization, the American Action Network is not required to publicly disclose its donors. Network spokesman Dan Conston did not comment on its contributors.
At least one campaign finance watchdog group has lobbied the IRS to strip the American Action Network's tax-exempt status, arguing that its a political action group that raised money to air attack ads against Democrats in the 2010 congressional elections, not a think thank concerned with social welfare.
During the June to July period, the network spent more than $25 million on advocacy, organizing and political activity. The group also donated money to other conservative groups, including almost $500,000 to American Crossroads, a super PAC linked to Republican strategist Karl Rove, who served as a senior advisor to former President George W. Bush.
"The 990 confirms that the American Action Network's primary purpose has been and remains to advocate for the implementation of center-right policies that we believe enhance American social welfare," Conston said in a statement.
"To the extent we participate in candidate advocacy, we comply with all rules and classifications from the IRS and the [Federal Election Commission]. The Network gave grants for general support to like-minded organizations that advance center-right policies. With regard to our sole political grant, the Network did so because we supported the political activities American Crossroads was engaged in."
The tax filing reports Coleman's annual compensation as $246,900 per year and lists former Republican U.S. Rep. Vin Weber, a Washington lobbyist and policy advisor to Mitt Romney's presidential campaign, as an unpaid director.
Coleman lost his Senate re-election bid to Sen. Al Franken in 2008. Weber retired from Congress in 1992.