U.S., U.K. and Swiss authorities alleged a vast conspiracy led by UBS AG to rig interest rates tied to trillions of dollars in loans and other financial products, indicating the practice was far more pervasive than previously known.

UBS agreed to pay about $1.5 billion to settle charges against the Swiss bank, and a unit in Japan where much of the wrongdoing occurred pleaded guilty to criminal fraud. U.S. prosecutors also filed criminal conspiracy charges against two former UBS traders allegedly at the heart of the scheme.

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