Barclays will pay $450 million to U.S. and British regulators to settle allegations that it rigged the interbank lending rate known as Libor, marking the first resolution in a sweeping investigation of the world’s largest banks.

Libor, the London interbank offered rate, is a standard interest rate for loans between banks that serves as a benchmark for more than $360 trillion in lending to businesses and consumers.

The British bank admits to scheming to manipulate rates to increase profits and hide the reality of its distress during the financial crisis. Regulators suspect Barclays did not act alone, but was part of a larger conspiracy to set artificially low rates for Libor and the Euro interbank offered rate, or Euribor.

The U.S. Commodities Future Trading Commission uncovered evidence of Barclays senior management and numerous traders in London, New York and Tokyo making false reports to improve the bank’s trading position dating to 2005, according to the complaint filed Wednesday. At the height of the recession, the bank submitted low figures to keep rates down and to deflect public scrutiny about its condition.

“When a bank acts in its own self-interest by attempting to manipulate these rates for profit, or by submitting false reports . . . to lower submissions to guard the bank’s reputation, the integrity of benchmark interest rates is undermined,” David Meister, director of enforcement at the CFTC, said in a statement.

Barclays agreed to pay $200 million to the commission and another $92.8 million to Britain’s Financial Service Authority for its actions. The bank will also hand over $160 million to the U.S. Justice Department’s criminal division but will not face criminal charges.

Assistant Attorney General Lanny Breuer said Barclays was the first bank to cooperate with the investigation in any meaningful way. Information provided by Barclays is being used in ongoing criminal investigations into other banks and bank employees. The agency would not disclose names or the number of banks involved in the probe.

In an apologetic statement, Barclays Chief Executive Bob Diamond announced that he and three senior executives are forgoing bonuses for the year in response to the case. He said the past actions “fell well short of the standards” the bank tries to uphold.

“I am sorry that some people acted in a manner not consistent with our culture and values,” he said.

Many market watchers said the settlement confirmed what was common knowledge in financial circles.

“There were suspicions that the banks were not being totally truthful in what they were reporting in 2008,” said James Angel, a professor of finance at Georgetown University’s McDonough School of Business. “As soon as that hit the media, Libor immediately jumped.”

About a dozen financial institutions, including Bank of America, HSBC and JPMorgan, submit data to set the daily Libor rate. That information is collected on behalf of the British Bankers’ Association by Thompson Reuters, which calculates the averages and devises the Libor rate.

Critics of the system say there is not enough transparency in how banks set their daily rates, which leaves the process wide open to fraud.

“This is an example of how letting the market regulate itself doesn’t work,” said attorney Brett Kappel of Arent Fox. “Given that the private sector has proven itself to be vulnerable to fraud, the next logical step would be to have the Libor rate determined by a government body.”

Kappel anticipates that the Barclays settlement will serve as a warning to other banks, but questions whether it will have enough impact to tighten regulations. The public, he said, does not know or understand how interbank rates affect their access to capital and therefore will not fight for changes to the system.

Regulators around the world have ramped up efforts to rein in impropriety. Earlier in the year, Swiss bank UBS said it was assisting Canada’s Competition Bureau in an investigation of interest-rate fixing in North America, Europe and Asia. Japanese banks are also looking into interbank rates.