From wikipedia :
After the Clinton Administration, Browner became a founding member of the Albright Group, a "global strategy group" headed by former U.S. Secretary of State Madeleine Albright.[29] As a Principal in that firm, Browner assists businesses and other organizations with the challenges of operating internationally, including the challenges of complying with environmental regulations and climate change. Coca-Cola and Merck have been among the clients for such international assistance.[13]
Her 2008 income was between $1 million and $5 million from lobbying firm Downey McGrath Group, where her husband is a principal.[42] She also reported $450,000 in "member distribution" income, plus retirement and other benefits from The Albright Group.[42]
Also from wikipedia under 'Albright Group':
The Albrigt Group (founder Madeline Albright) The firm assists businesses and other organizations with operating internationally, including the challenges of complying with environmental regulations and climate change. Coca-Cola and Merck have been among the clients for such assistance.[3]
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So there you have it. Now you know where her money comes from.
In other words, from her role in govt she helps formulate environmental policies and regulations, and then “assists” (milks) companies to comply with or work around those policies.