The firm has a number of major K Street lobbying firms on the corporate list. | John Shinkle/POLITICO CAP releases donor list

The liberal think tank Center for American Progress on Friday revealed that it's funded by some of the country's largest and most powerful corporations, trade associations and lobbying firms.

Major donors to the group and its affiliate social welfare nonprofit Center for American Progress Action Fund include major retailers, energy interests, health care companies and other corporate actors who spend millions on lobbying and influence peddling in the nation's capital, according to a list posted on the center's website.

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The group — which is a fundraising powerhouse that takes in about $40 million a year — released its donor list as founder and chairman John Podesta heads into the Obama White House to serve as a senior adviser.

Those corporations and trade associations represent a cross section of corporate America and include Walmart, Goldman Sachs, Google, defense giant Northrop Grumman, T-Mobile, Toyota, Visa, GE, among others. CAP did not disclose the donation amounts.

America's Health Insurance Plans, or AHIP — a major player in the health care debate contributed to the group, as did Hollywood's advocacy arm, the Motion Picture Association of America. Other corporate donors include Microsoft, PepsiCo, Samsung, CVS Caremark, Comcast NBCUniversal and many others.

The firm also has a number of major K Street lobbying firms on the corporate donor list including Akin Gump, the Glover Park Group, Livingston Group and the Downey McGrath Group. All represent dozens of corporate and nonprofit clients.

CAP officials stressed that Podesta personally was not involved in soliciting donations from many of those corporations — saying that he gave up his role in fundraising two years ago.

"I don't think he even knows who our corporate supporters are," CAP president Neera Tanden told POLITICO Thursday.

Podesta founded CAP in 2003 as a counterweight to conservative think tanks like the Heritage Foundation and the American Enterprise Institute. The group produces research reports and runs the popular liberal website ThinkProgress.

The release of CAP's donors also comes amid concerns about corporate influence peddling and think tanks.

Sen. Elizabeth Warren (D-Mass.) — a darling of progressive activists — challenged banks and other financial institutions to fully disclosure their contributions to think tanks in a letter last week.