Among the first moves Barack Obama made as the presumptive Democratic presidential nominee this week was to reform the Democratic National Committee's fundraising rules. No longer will the party accept contributions from federal lobbyists or political committees, he announced in a statement: "[Washington lobbyists and special interest political committees] do not fund my campaign. They will not fund our party. And they will not drown out the voices of the American people when I'm President of the United States."

It's a significant reform. But when Obama and other Democrats migrate to Denver this August for the party convention, they will enjoy an event funded largely by corporations as a result of a fundraising effort led by a lobbyist.

On Wednesday, the Campaign Finance Institute, a nonpartisan D.C. watchdog, issued a report on fundraising for both parties' conventions. Due to a "gigantic loophole" in campaign finance laws, the report says, corporations can give unlimited amounts to the conventions' host committees, contributions that would be illegal if given directly to the parties.

Heading up the fundraising for the Denver convention is Steve Farber, a registered federal lobbyist with the firm Brownstein Hyatt Farber Schreck. Among the dozens of corporate sponsors of the Denver convention are six of his firm's clients (United Health Group, AT&T, Comcast, the National Association of Home Builders, Western Union and Google) and the firm itself. The CEO of the host committee is Mike Dino, a registered federal lobbyist with Patton Boggs.

Farber and other Colorado Democrats leading the fundraising effort have aimed to raise $55 million, most of which was expected to come from out-of-state contributions. Denver’s mayor John Hickenlooper told The Denver Post last December that he and the other Democrats involved in fundraising for the convention (including Sen. Ken Salazar, Gov. Bill Ritter and Rep. Diana DeGette) had already traveled 20,000 miles and spoken to people from 60 to 80 companies.

In return for their contributions, major donors are promised access. Corporate fundraising materials used by the Denver host committee and obtained by the Campaign Finance Institute show that donors at the “Presidential Sponsor” level ($1 million and up) get VIP credentials at the convention, an invitation to a private event with a number of Colorado lawmakers and first consideration for renting “premier Denver venue space for corporate hospitality events.”

As the report detailed, Republicans were initially bolder with the perks offered to generous corporations who supported their convention in Minneapolis: Donors above the $5 million level were promised, among other goodies, a private dinner and a golf outing with the Republican leadership. But after reports on that offer last year, the host committee dropped the dinner and golf quality time from its fundraising materials. Talking points for Minnesota Gov. Tim Pawlenty’s pitch at a CEO fundraising breakfast last June, also obtained by the Campaign Finance Institute, show a similarly enticing promise: “We plan to have various events with Cabinet/VP and other elected officials to thank donors for their contributions.” Besides being rumored as a possible pick to be John McCain’s vice presidential nominee, Pawlenty has served as a co-chair of McCain’s presidential campaign.

Matthew Schwarzfeld contributed research to this story.