UBS AG's $1.5 billion settlement for manipulation of interest rates and criminal charges against two former traders paves the way for additional sanctions in a global investigation of more than a dozen banks and brokers.

Switzerland's biggest bank settled with U.S., U.K. and Swiss regulators for manipulating rates thousands of times over six years through relationships with multiple banks and brokers. Two traders were charged with conspiracy in a criminal complaint, while UBS's Japanese affiliate pleaded guilty in the U.S. to felony wire fraud. Hong Kong authorities today said they've started a probe into potential misconduct by the bank.

"UBS sometimes acted alone, sometimes in two-way collusion with at least four other banks and sometimes it violated the law with the assistance of one or more of five inter-dealer brokers," David Meister, head of enforcement at the U.S. Commodity Futures Trading Commission, said in a news conference in Washington.