Bloomberg: “Some secret donors who gave money to groups that paid for millions of dollars in attack ads during the 2010 midterm elections are becoming public. Chevron Corp. (CVX), an oil and gas company; Merck & Co. (MRK), a drug maker; and the American Petroleum Institute are among the entities that have disclosed through corporate filings or Internal Revenue Service reports their donations to politically active groups that are growing in influence. The non-party organizations that don’t disclose their donors increased their spending to $133 million in 2010, compared with $875,000 during the previous off-year elections in 2006, according to the Center for Responsive Politics, and favored Republicans by a ratio of 10-to-1.”