The United States government has announced a rescue plan for the Citigroup banking giant after its shares plunged by more than 60% last week.
The US Treasury Department is to invest $US20 billion in return for preferred shares in Citigroup.
The Treasury and the Federal Deposit Insurance Corp will also guarantee up to $US306 billion of risky loans and securities on Citigroup's books.
The plan follows a $US25 billion injection of public funds in the bank in October.
Citigroup's market value fell to $US20.5 billion on Friday, compared with $270 billion in 2006.
Last week the company announced 52,000 job losses worldwide, on top of 23,000 job cuts previously announced.
Citigroup has lost more than $US20 billion in the past year because of the global financial crisis, suffering four straight quarterly losses.
The action plan was announced after emergency talks over the weekend between the bank and the Treasury Department, the Federal Reserve and the Federal Deposit Insurance Corp.
Citigroup is one of the leading American banks and has operations in more than 100 countries.
Many analysts had calculated that the huge financial institution was too big to allow to fail.