The study by the non-partisan watchdog Center for Public Integrity found that four of the five biggest bundlers of campaign contributions among lobbyists were Democrats who raised a combined $1 million for the Democratic Congressional Campaign Committee alone.
Other beneficiaries were the Democratic Senatorial Campaign Committee, Senate Majority Leader Harry Reid, House Speaker Nancy Pelosi and New York Senator Charles Schumer, the study showed.
Bundlers, who collect large aggregate sums of individual contributions for candidates, national party committees and political action committees, play a major role on the U.S. political landscape, particularly during presidential campaigns.
But only since February 2009 have campaign committees had to disclose their top lobbyist bundlers in filings listed in a Senate database.
All 435 members of the House of Representatives and 36 of the Senate's 100 seats are up for election in November, with Democratic control of both chambers at risk.
The Center for Public Integrity found fundraising records for only 96 of the 14,847 registered federal lobbyists. They raised a combined $6 million in contributions for 63 candidates, PACs and party committees from February through December 2009.
The biggest bundler was Texas Democrat Ben Barnes, who raised $641,950 for the DCCC or more than 70 percent of the campaign committee's total bundled donations between July and December.
Anthony Podesta, brother of former White House Chief of Staff John Podesta, was the second biggest bundler with $394,900 that included donations to the party's House and Senate campaign committees as well as Reid and fellow Senate Democrat Patty Murray.
The only Republican lobbyist to break into the top five was former Senate aide Frederick Baird, who raised $210,300 for the National Republican Senatorial Campaign Committee, House Republican Jeb Hensarling and Senate Republicans Tom Coburn and Jim DeMint.
President Barack Obama relied heavily on bundlers during his 2008 White House campaign, with nearly 50 fundraisers collecting at least $500,000 apiece from friends, colleagues and other sources, according to another nonpartisan watchdog, the Center for Responsive Politics. Obama's biggest bundled contributions came from the legal, securities and entertainment industries.
Source Reuters (Reporting by David Morgan; editing by Mohammad Zargham)