The US government is trying to get the $225m+ it is owed by American Financier Sir Allen Stanford. It is made up of taxes, penalties and interest.
The IRS tax agency has filed a request with a judge in Texas to chase the alleged bill dated back to 1999.
Sir Allen is also yet to file his 2007 tax return.
Although he is being investigated for an alleged $8bn fraud, Sir Allen is yet to be indicted on criminal charges.
Documents seen seem to indicate that he has so far refused to talk to the US regulators who are investigating the alleged fraud.
The civil case against Sir Allen has been brought by the Securities and Exchange Commission.
It is expected that forensic accountants will play a key role in the investigation.