A significant chunk of the donor base for the presidential coffers of Sen. Chris Dodd (D-Conn.), who chairs the Senate Banking Committee, appears to be tapped out. Newly released third-quarter fundraising numbers show that contributions from the financial services sector have plummeted to less than $400,000 from just more than $2 million in the first quarter.

At the same time, financial services executives and lobbyists said the Dodd campaign’s fundraising pleas aimed at their sector have not cooled but actually intensified.

“It’s just relentless. It’s unending,” said one financial services executive based in Washington, D.C., who, like the others, would only speak if he were not identified for fear of upsetting Dodd or Dodd’s staff members.

This financial services executive, who is a supporter of another Democratic primary candidate and

lobbies the Senate Banking Committee, added, “We’re all under the same anvil, but they’re squeezing blood from a turnip. There’s nothing left in there.”

Dodd initially turned his gavel into a powerful fundraising force for his long-shot White House effort. In the first quarter, more than half of his contributions came from employees or political action committees of banks, securities firms and other financial services institutions.

But by the third quarter, which ended Sept. 30, Dodd’s support among that set had decreased to 27 percent, according to an analysis of Federal Election Commission data compiled by the nonpartisan Center for Responsive Politics. The data show a steady decline of support from an increasingly tapped-out sector. In the first quarter, financial services PACs and executives donated 52 percent of Dodd’s $4 million in new contributions. In the second quarter, that percentage had fallen to 38 and by the third quarter just 27 percent of his $1.5 million came from financial services types.

Although Dodd’s public supporters on K Street are few — most lobbyists who have publicly endorsed a Democratic presidential candidate have lined up behind Sen. Hillary Rodham Clinton (D-N.Y.) — one Dodd supporter, OB-C Group founder Larry O’Brien, said the drop off in money coming in from financial services may be just a “natural decline curve” in the sector, whose generosity has perhaps mostly maxed out.

“I do think there was really a dramatic early effort made with what one would call his natural constituencies, up in the Northeast in New York and Connecticut,” said O’Brien, whose registered clients include private equity giant Kohlberg Kravis Roberts & Co. and JPMorgan Chase, according to lobbying filings.

Dodd campaign communications director Hari Sevugan disputes the notion that the campaign relied mainly on one sector of the economy for its contributions.

“This was never a campaign that was based on [the idea] that our primary source of money was going to come from the financial services industry,” Sevugan said in a telephone interview. “We’ve always said we’re going to have a wide range of support as the campaign goes on.”

One financial services industry lobbyist said the Dodd campaign is savvy enough to know that by applying pressure on the lobbyists, those K Streeters can then take the demands back to the home office and try to encourage executives throughout the company to pay into Dodd’s presidential coffers. “It’s the lobbyists that are constantly coming into the [Dodd] office,” one lobbyist said. “They’re the ones that have the most to lose.”

Sheila Krumholz, executive director of the Center for Responsive Politics, said she is not surprised that lobbyists and financial services executives are feeling increasing pressure from the Dodd campaign.

“I think the pressure is going to come to a fever pitch,” she said. “This is the make-or-break time prior to the primaries. I think it’s not surprising for a campaign to pull out the stops particularly with their core supporters, to make sure they’re not only maxing out but also delivering their colleagues and their network.”

As Dodd continues to flounder in the presidential polls, financial services lobbyists say that getting their outside-the-Beltway colleagues to donate is becoming more difficult.

Despite that, donations from the financial services sector have come, and from both sides of the aisle. Even former Rep. Steve Bartlett (R-Texas), who is the CEO of the Financial Services Roundtable, has become a bundler for Dodd.

All the lobbyists and financial sector executives interviewed said no one from the Dodd campaign specifically has tied any giving to any Senate actions. But the lobbyists said that Dodd’s fundraisers are adept at using the subtleties of Washington language to make sure they communicate a message that they are aware of who has given, and who has not.

“It’s very disappointing that Roll Call would publish blind accusations that simply are not true,” Sevugan said in a statement he read over the phone. “Chris Dodd’s fundraising and actions as a U.S. Senator have always been independent of one another and his record, including leading on credit card and predatory lending reform, bear that out.”

As for why the donations from givers with ties to financial services have declined, one Republican lobbyist said, “There’s only so much and so many people to raise money from in the sector. The people who are the most willing to give, give it early. There are limits.”

Some lobbyists say the pressure from Dodd’s campaign is no different from any other presidential candidate.

“I don’t think they’ve put any undue pressure on the sector,” said an in-house lobbyist with a financial services institution who supports another Democratic candidate for the White House. “I don’t think they’ve done anything untoward. It’s just presidential candidates. They call a lot of people. It’s the same thing on the Republican side. To his credit, Sen. Dodd has been able to separate out that he’s chairman of the banking committee and being a presidential candidate.”

For the lobbyists who are complaining, Krumholz said she has no sympathy

“Lobbyists , PAC directors, fundraisers in D.C., have long said they do not like the extortionary tactics of campaigns and that they hate the system of being hit up,” she said. “On the other hand, when they do give contributions, there’s ample evidence that they want something in return. You can’t have it both ways.”