Business lobbyists and several of their key Republican House allies spent Wednesday in a flurry of activity — a conference call, a press conference and the issuance of a lengthy analysis by the U.S. Chamber of Commerce. All of it was aimed at undercutting a series of hearings today by House and Senate Democrats on proposed tax increases on private equity firms and other partnerships.

Not surprisingly, the chamber’s 41-page report, complete with full-color pie charts, graphs and summaries of historical studies on the issue, concluded that any tax increase to partnerships or private equity funds would hurt the economy. “Raising tax rates would … undermine investment, innovation, entrepreneurial activity, and productivity,” the study’s executive summary stated. “It will cost American jobs and reduce American incomes.”

Reps. Eric Cantor (R-Va.) and Tom Reynolds (R-N.Y.), both seeking to be go-to Members for the business community in the ongoing debate, held a press conference and, citing the chamber’s report, blasted Democrats for planning today’s marathon Ways and Means Committee hearing. Titled a “Fair and Equitable Tax Policy for America’s Working Families,” the hearing has a witness list of some 20 experts, including academics, think tank members and private equity fund partners. The Senate Finance Committee also is holding a hearing today on the private equity tax issue.

Cantor called a proposed bill sponsored by Ways and Means Chairman Charlie Rangel (D-N.Y.) and Rep. Sander Levin (D-Mich.) to increase the taxes paid by private equity funds “a direct assault on private investment,” adding that it would hurt not only large financial services funds but “mom-and-pop” partnerships as well. Democrats, Cantor added, are employing what he derided as “bumper-sticker populism.”

Reynolds called the Ways and Means panels “stacked for the Democrats’ message” and said increased taxes on the private equity sector would reverse gains in job growth. “Congress should be doing the opposite,” he said, “simplifying the tax structure.”

Democrats say the issue is one of fairness, adding that there is something wrong with a tax system in which partners in highly profitable private equity jobs are paying a lower tax rate than average Americans pay in their income taxes.

In the Senate, the Blackstone bill, named for the private equity fund Blackstone Group, would boost the tax rate on the profits of private funds that go public to 20 percent. The House proposal would increase the taxes paid on “carried interest,” the fund managers’ cut if a deal is profitable, from the current 15 percent capital gains rate to a higher corporate income rate of about 35 percent.

For its part, the chamber said its analysis showed that proposals to increase the tax rate on partnerships is a bad idea.

“It is unequivocal that the returns to pension funds and charitable endowments would decline following such a tax increase,” Rutledge Capital Chairman John Rutledge said during a conference call with reporters. Rutledge conducted the chamber’s report.

Rutledge said that partnerships are the cornerstone of American business and are used in sectors from agriculture, oil and gas, food and hotels to financial services and real estate. Leaders in China, he said, are watching what Congress does in the hopes of attracting that capital — the jobs it would bring — overseas. “They’re waiting for us to make a mistake that would drive capital into their welcoming arms,” he said.