In a remarkable illustration of the power of lobbying in Washington, a study released last week found that a single tax break in 2004 earned companies $220 for every dollar they spent on the issue -- a 22,000 percent rate of return on their investment.

The study by researchers at the University of Kansas underscores the central reason that lobbying has become a $3 billion-a-year industry in Washington: It pays. The $787 billion stimulus act and major spending proposals have ratcheted up the lobbying frenzy further this year, even as President Obama and public-interest groups press for sharper restrictions on the practice.

The paper by three Kansas professors examined the impact of a one-time tax break approved by Congress in 2004 that allowed multinational corporations to "repatriate" profits earned overseas, effectively reducing their tax rate on the money from 35 percent to 5.25 percent. More than 800 companies took advantage of the legislation, saving an estimated $100 billion in the process, according to the study.

The largest recipients of tax breaks were concentrated in the pharmaceutical and technology fields, including Pfizer, Merck, Hewlett Packard, Johnson & Johnson and IBM. Pfizer alone repatriated $37 billion, representing 70 percent of its revenue in 2004, the study found. The now-beleaguered financial industry also benefited from the provision, including Citigroup, J.P. Morgan Chase, Morgan Stanley and Merrill Lynch, all of which have since received tens of billions of dollars in federal bailout money.

The researchers calculated an average rate of return of 22,000 percent for those companies that helped lobby for the tax break. Eli Lilly, for example, reported in disclosure documents that it spent $8.5 million in 2003 and 2004 to lobby for the provision -- and eventually gained tax savings of more than $2 billion.

"There's always been speculation that lobbying is a lucrative area," said Stephen W. Mazza, a Kansas tax-law professor who is one of the authors of the study. "We've been able to come up with quantifiable returns and show that it really is the case."

Mazza added that the results are "troubling" because they show how large companies can distort tax policy to benefit their bottom line.

Obama has made lobbying a key target of his ethics policies, sharply limiting the access of lobbyists to the administration and forbidding the appointment of many former lobbyists in the government without special waivers. The moves have angered many lobbying groups but have had little apparent impact on the ongoing boom in K Street business.

"It's always hard to measure the financial benefits of lobbying, but generally everyone knows it does bring in a lot," said Craig Holman, government affairs lobbyist for Public Citizen. "That's why corporations are pouring more and more money into lobbying every year. Clearly, they understand it has a very good rate of return."

The tax break in question was included as part of the American Jobs Creation Act of 2004, and was billed as a way to create jobs in the United States by requiring companies to use the money for specific purposes.

But the Congressional Research Service and others have since found that many companies cut jobs in the wake of the tax break and that nearly all the money was used for stock buybacks or dividends. Supporters failed in a bid to include a similar tax break in this year's stimulus legislation, and a Senate subcommittee has launched an investigation into how companies used their tax savings under the 2004 program.

The provision was championed in part by the Homeland Investment Coalition, a group of companies and trade associations that was formed to push for the repatriation holiday. The Pharmaceutical Research and Manufacturers of America (PhRMA), one of the disbanded coalition's members, said in a statement Friday that "repatriation of profits provided a new source of investment for American companies."

"PhRMA supported the legislation four years ago as part of a broad business coalition because of the additional economic benefits the bill would provide," senior vice president Ken Johnson said. "It meant jobs and skilled training for American workers, as well as a shot in the arm for local economies."