A group of 17 US legislators asked the Securities and Exchange Commission on Thursday to release all documents related to its civil investigation of Sir Allen Stanford, the Texan billionaire accused of perpetrating an $8bn “Ponzi” scheme.

In a letter sent to Mary Schapiro, the SEC chairman, a group made up of both Republicans and Democrats asked for internal memos and information received by the SEC that discussed the potential fraud by Sir Allen and his associates.