Feb. 18 (Bloomberg) -- U.S. regulators don’t know the whereabouts of R. Allen Stanford, the billionaire accused of running a “massive, ongoing fraud” through his Houston-based Stanford Group Co., a Securities and Exchange Commission official said.

“We don’t know where he is, quite frankly,” said Rose Romero, director of the SEC’s office in Fort Worth, Texas.

The SEC yesterday filed a civil lawsuit against Stanford, companies he controls and two colleagues, claiming they misled investors while selling $8 billion in certificates from an affiliated bank in Antigua. He hasn’t been criminally charged, a step that could restrict his movements.

The SEC and a court-appointed receiver are seeking to locate investor assets to determine any possible losses. The agency said Stanford, 58, has “wholly failed to cooperate” with U.S. efforts to account for investor funds at Antigua-based Stanford International Bank. About 90 percent of the firm’s investment portfolio is essentially a “black box,” shielded from independent oversight, the regulator said.

Stanford has offices in Panama, Venezuela, Mexico, Ecuador, Peru and Colombia.

Allen Stanford, who last year was named the 605th wealthiest person in the world by Forbes magazine, has six planes registered with the Federal Aviation Administration, according to the agency’s Web site. He is a citizen of the U.S. and of Antigua & Barbuda after being naturalized in that country 10 years ago, according to a biography from the company’s Web site. Stanford Group has 19 wealth management offices in the U.S., according to its Web site.

Alfredo Perez, a spokesman for the U.S. Marshall’s office in Houston, which yesterday raided the company’s offices there, said he isn’t aware of any arrest warrant for Stanford. U.S. Attorney General Eric Holder, speaking with reporters in Washington today after a Black History Month event at the Justice Department, declined to comment on the case.

To contact the reporter on this story: David Scheer in New York at dscheer@bloomberg.net.

Last Updated: February 18, 2009 12:56 EST