A spokesman for Stanford Group declined to comment.

Law enforcement officials hung up two white signs stating that the offices of Stanford Financial Group were temporarily closed. “The company is still in operation but under the management of a receiver,” the signs read.

In its complaint, the S.E.C. said it could not account for the $8 billion in assets that were housed in the Antigua bank after issuing subpoenas for bank records and to various witnesses. Most witnesses, including Mr. Stanford, Mr. Davis and the Antigua-based bank’s president, failed to appear to testify and did not provide any documents shedding light on the assets.