Bloomberg LP, the parent company of Bloomberg News, has requested the information is disclosed under the Freedom of Information Act.
It wants to have access to 231 term sheets which contain details of Federal Reserve loans to financial companies in 2008.
But the Fed claims revealing the information will cause "severe and irreparable competitive injury" to the firms which borrowed money and lead to banks being discouraged from getting help when in trouble in the future.
It is petitioning the US Court of Appeal to delay bringing in a ruling that forces the Fed to hand over the information and, if successful, will have 90 days to ask the Supreme Court to reverse the previous decision to allow the data to be published.
Earlier this week, an insider told Bloomberg that the Fed is considering reducing AIG's credit line by $3.6 billion as a show of faith in the company.
By Gary Cooper