WASHINGTON — President Obama signed a bill on Wednesday that extends the life of the Export-Import Bank through 2014, ending an unexpectedly fierce political fight over an institution dedicated to financing American exports abroad.

Speaking at the signing ceremony to an audience filled with owners of small businesses, Mr. Obama said the reauthorization of the bank was critical to leveling the playing field with China and other countries, which provide similar credit to their export industries.

“We’re helping thousands of businesses sell more of their products and services overseas,” the president said, “and in the process, we’re helping them create jobs here at home. And we’re doing it at no extra cost to the taxpayer.”

Mr. Obama paid tribute to Congressional leaders who brokered the deal to preserve the bank, which was in jeopardy after Tea Party-aligned conservatives in the House and Senate seized on the need for reauthorization as a chance to mothball an agency they say is a purveyor of welfare to big corporations like Boeing and Caterpillar.

With the bank facing the imminent closing of its doors, business groups like the United States Chamber of Commerce and National Association of Manufacturers mobilized a strong lobbying effort that pitted traditional Republican interests against the Tea Party insurgency. The White House threw its support behind efforts to find a compromise.

In the House, the Republican leader, Representative Eric Cantor of Virginia, reached a deal with the minority whip, Representative Steny Hoyer of Maryland, under which the bank’s lending limit would be increased to $140 billion over three years, from the current $100 billion. In return, the bank will be subject to new auditing and reporting requirements, which critics said would help ensure that it did not waste taxpayer dollars.

Mr. Hoyer and other Democrats were present at the signing ceremony, though Mr. Cantor was not. Last month, he came to the Rose Garden to watch the president sign a bill easing restrictions for small companies to raise money from investors. This time, said his spokeswoman, Laena Fallon, “we weren’t able to make it work with his schedule.”

For the bank’s chairman, Fred P. Hochberg, the reauthorization brought relief after a nerve-rattling few months. Until this year, the reauthorization of the bank, which dates to the 1930s, had been a routine exercise.

“By signing this bipartisan bill into law, President Obama has once again demonstrated his strong commitment to America’s business owners, workers, and exporters,” Mr. Hochberg said in a statement. “The president has been a strong champion of Ex-Im Bank and, thanks to his leadership, more U.S. companies are exporting to more countries.”

Mr. Obama said the Export-Import Bank was critical to his goal of doubling American exports over five years — along with trade agreements with South Korea, Colombia, and Panama; and trade enforcement actions against China. He cited a recent sale of 200 airplanes by Boeing to a foreign airline as a deal that would not have been signed without the bank’s help.

“As long as our global competitors are providing financing for their exports, we’ve got to do the same,” Mr. Obama said. “So I’m glad that Congress got this done.”

The president then swiftly turned to other things that he said Congress needed to enact — a familiar list that includes streamlining the refinancing of home mortgages and tax breaks for companies that hire new workers.

“These are steps we can take right now to speed up this recovery, to help create jobs, to restore some of the financial security that families have lost,” Mr. Obama said. “It’s within our control to do the right thing and do it now.”