Nov. 17 (Bloomberg) -- More than 14,700 Americans voluntarily disclosed secret offshore bank accounts to the Internal Revenue Service during a partial amnesty program that ended Oct. 15, Commissioner Doug Shulman said.

“We were flooded with people coming in during the final days of the program,” Shulman told reporters on a conference call in Washington today as the U.S. and Swiss governments released a list of criteria used by Switzerland to screen American clients of UBS AG bank for tax fraud.

Americans with undeclared offshore accounts have been under growing pressure since Switzerland agreed Aug. 19 to hand over data to the U.S. on as many as 4,450 UBS accounts to settle a lawsuit in which the U.S. had sought as many as 52,000 accounts.

The more than 14,700 voluntary disclosures announced today are nearly double the amount the IRS reported a month ago. They are in addition to the accounts UBS must turn over to the IRS under the settlement.