UPDATE 1-Stanford ex-CFO Davis gets 5-year prison sentence

(Adds details from hearing)

HOUSTON, Jan 22 (Reuters) - James Davis, the government's top witness in convicted swindler Allen Stanford's fraud trial, was sentenced on Tuesday to five years in prison for his role in a $7 billion Ponzi scheme.

Davis, 64, who could have been sentenced to 30 years, told the court in a breaking voice: "I am ashamed and I am embarrassed." He added that he let down his family and thousands of investors.

U.S. District Judge David Hittner cited Davis' cooperation with prosecutors when he handed down the punishment.

Davis' lawyer, David Finn, had asked for a four-year sentence while prosecutors sought a 10-year sentence.

Stanford was convicted last year of bilking thousands of investors using fake certificates of deposit issued by Stanford International Bank in Antigua. He is serving a 110-year prison term in Florida.

At Stanford's 2012 trial the former chief financial officer told jurors that he and Stanford used fake accounting to prop up his offshore bank as withdrawal requests poured in during the financial crisis in 2008.

(Reporting By Anna Driver and Eileen O'Grady; Editing by Gerald E. McCormick and David Gregorio)