text: As of early 2008, the targeted banks, such as Bank Mellat, had been able to replace banking relationships with a few large sanction-compliant banks with relationships with a larger number of smaller non-compliant banks. In 2008, the United States Department of the Treasury ordered Citigroup Inc. to freeze over $2 billion held for Iran in Citigroup accounts.
  For individuals and small businesses, these banking restrictions have created a large opportunity for the hawala market, which allows Iranians to transfer money to and from foreign countries using an underground unregulated exchange system. In June 2010, in the case United States v. Banki, the use of the hawala method of currency transfer led to a criminal conviction against a U.S. citizen of Iranian origin. Banki was sentenced to two and a half years in federal prison; however, on the sentencing guidelines, this type of offense could result in imprisonment of up to 20 years.
  Obama presidency
  On June 24, 2010, the United States Senate and House of Representatives passed the Comprehensive Iran Sanctions, Accountability, and Divestment Act of 2010 (CISADA), signed into law by President Obama on July 1, 2010. The CISADA greatly enhanced restrictions on Iran, including the rescission of the authorization for Iranian-origin imports for articles such as rugs, pistachios, and caviar. In response, President Obama issued  in September 2010 and  in May 2011, and  in November 2011.