Groups representing retirees, corporate executives and small-business owners are mounting a furious last-minute lobbying effort in support of a $700 billion rescue plan for the financial markets.

Leaders of the AARP, the Business Roundtable and the National Federation of Independent Business (NFIB) said their own members have increasingly called or e-mailed their Washington offices to relate stories about how the financial crisis is affecting them.

Those personal accounts are being turned into a grassroots campaign to provide a counterweight to the thousands of calls and e-mails from voters urging members to reject the plan as a massive, taxpayer-funded bailout of Wall Street.

“They are angry at the idea of bailing out Wall Street,” said Bill Novelli, chief executive officer of AARP. “In this case, Wall Street is us. Wall Street is our stocks, our investments.”

Novelli on Wednesday joined the leaders of the Business Roundtable and the NFIB in a teleconference briefing reporters on the groups’ lobbying strategy.

John Castellani, president of the Business Roundtable, which represents the top executives of the nation’s largest companies, said his members are already feeling the effects of the credit crunch.

“They can’t get a car loan. They can’t get a loan for inventory purchases. They can’t get a loan to refinance their payroll,” Castellani said.

Novelli said AARP members have sent in about 110,000 e-mails to congressional offices since Saturday in support of the bill. The group, which advocates for retirees, sent out another action alert Wednesday.

“People are calling in great fear because they are seeing their 401(k)s drying up,” said Novelli. “People are asking, ‘I retire on dividends. What do I do now?’ ”

NFIB, meanwhile, has worked with the Treasury Department to craft the rescue plan that supports small businesses. Its leadership participated in a conference call with Treasury Secretary Henry Paulson earlier this week and was scheduled to host another with Paulson later on Wednesday (after press time).

Chief executive officers have been calling lawmakers who represent districts where their businesses are based, urging support for the bailout. There is also an advertising campaign directed primarily at audiences on Capitol Hill that was to start Wednesday.

So far, calls to members’ offices have been overwhelmingly against the bailout plan, according to members, congressional staff and lobbyists. The hope is the latest campaign will reassure reluctant members about the support for the bailout that exists in their districts.

Backers in the administration and in Congress have also been working to attract broader support, in particular by raising the amount of federal insurance on deposits to $250,000, up from the current limit of $100,000.

Todd Stottlemyer, NFIB’s president and chief executive officer, said his trade group welcomed that change.

“This will give small businesses greater confidence that their business assets are indeed secure,” Stottlemyer said.

Not everything these groups wanted is in the bailout bill the Senate was scheduled to vote on Wednesday night. AARP, for example, had lobbied for a provision that would give bankruptcy judges the discretion to restructure mortgage debt to help distressed homeowners. But the Senate did not include that provision, which was vigorously opposed by much of the business lobby.

These groups had urged passage of the bill last week, and along with other groups like the Financial Services Roundtable and the U.S. Chamber of Commerce, had urged the House on Monday to pass the bailout package that had emerged after a long week of intense negotiations among congressional leaders and administration officials.

Castellani said he was surprised that large blocs of representatives from California, Georgia, Ohio and Texas moved against the agreement. He and others are trying to flip those “no” votes to yes when the House takes it up again, as early as this Thursday.

“Our target list is 535 people long. Well, maybe we have eliminated the leaders, so 528,” Castellani said.