The nation’s top corporations gave more than $185 million in 2012 to tax-exempt groups that spent heavily on politics and lobbying, according to a report released today by the Center for Public Integrity. The report discloses for the first time the extent to which blue chip companies such as Exelon, Microsoft and WellPoint bankroll the activities of leading trade associations, advocacy groups and think tanks. An investigative journalism nonprofit, the center pored over voluntary disclosures filed by the companies that Fortune magazine ranks as the nation’s top 300. The seven-month investigation covering the 2012 calendar year identified 1,000 politically active nonprofits underwritten by the corporate expenditures. More than two dozen such groups collected at least $1 million each from corporate givers, the report found. Since tax-exempt groups need not disclose their donors, watchdogs have dubbed their political spending "dark money." (more…)