WASHINGTON (AP) - Billions of dollars in U.S. taxes are going unpaid because Americans are exploiting Swiss bank accounts, and the U.S. government has failed to aggressively pursue Switzerland's second-largest bank, a Senate investigation has found.

WASHINGTON (AP) Billions of dollars in U.S. taxes are going unpaid because Americans are exploiting Swiss bank accounts, and the U.S. government has failed to aggressively pursue Switzerland's second-largest bank, a Senate investigation has found.

The bank, Credit Suisse, has provided accounts in Switzerland for more than 22,000 U.S. clients totaling $10 billion to $12 billion, according to a report issued Tuesday by the Senate Permanent Subcommittee on Investigations. The U.S. government has received only 238 names of U.S. citizens with secret accounts at Credit Suisse, or just 1 percent of the estimated total, the investigation concluded.

Credit Suisse recruited U.S. clients to open Swiss accounts from 2001 through 2008, helped them conceal the accounts from the Internal Revenue Service and enabled misconduct by bank employees, the subcommittee asserted.