Over the last decade, G.E. has spent tens of millions of dollars to push for changes in tax law, from more generous depreciation schedules on jet engines to “green energy” credits for its wind turbines. But the most lucrative of these measures allows G.E. to operate a vast leasing and lending business abroad with profits that face little foreign taxes and no American taxes as long as the money remains overseas.

Company officials say that these measures are necessary for G.E. to compete against global rivals and that they are acting as responsible citizens. “G.E. is committed to acting with integrity in relation to our tax obligations,” said Anne Eisele, a spokeswoman. “We are committed to complying with tax rules and paying all legally obliged taxes. At the same time, we have a responsibility to our shareholders to legally minimize our costs.”

The assortment of tax breaks G.E. has won in Washington has provided a significant short-term gain for the company’s executives and shareholders. While the financial crisis led G.E. to post a loss in the United States in 2009, regulatory filings show that in the last five years, G.E. has accumulated $26 billion in American profits, and received a net tax benefit from the I.R.S. of $4.1 billion.

But critics say the use of so many shelters amounts to corporate welfare, allowing G.E. not just to avoid taxes on profitable overseas lending but also to amass tax credits and write-offs that can be used to reduce taxes on billions of dollars of profit from domestic manufacturing. They say that the assertive tax avoidance of multinationals like G.E. not only shortchanges the Treasury, but also harms the economy by discouraging investment and hiring in the United States.

“In a rational system, a corporation’s tax department would be there to make sure a company complied with the law,” said Len Burman, a former Treasury official who now is a scholar at the nonpartisan Tax Policy Center. “But in our system, there are corporations that view their tax departments as a profit center, and the effects on public policy can be negative.”

The shelters are so crucial to G.E.’s bottom line that when Congress threatened to let the most lucrative one expire in 2008, the company came out in full force. G.E. officials worked with dozens of financial companies to send letters to Congress and hired a bevy of outside lobbyists.

The head of its tax team, Mr. Samuels, met with Representative Charles B. Rangel, then chairman of the Ways and Means Committee, which would decide the fate of the tax break. As he sat with the committee’s staff members outside Mr. Rangel’s office, Mr. Samuels dropped to his knee and pretended to beg for the provision to be extended — a flourish made in jest, he said through a spokeswoman.