The Fed’s worries grew last summer when the chief federal district judge in Manhattan ruled in favor of Bloomberg News, setting up a showdown last month in the United States Court of Appeals for the Second Circuit. This appellate battle — which includes a similar suit by Fox News that lost in the district court — has quickly become the New York front in a bitter, two-pronged war against the Fed. (In Washington, legislation is pending to force the central bank to undergo an audit.) Indeed, as the lawsuit moved to its next round, its context was expanded by way of interventions and supporting briefs.

Now, two Manhattan tribes appear to be squaring off: On one side are the news media — among them The Associated Press, The Wall Street Journal and The New York Times, which also has a FOIA bailout suit and has agreed to be bound by the Second Circuit ruling. On the other side are the banks — JPMorgan Chase, Citibank, Bank of America and others — which, of course, have fallen in behind the Fed.

MR. Winkler, a slight man who favors bow ties, started his career covering the Fed for The Daily Bond Buyer decades ago. He said Bloomberg has often pursued information by way of litigation. In 1993, for instance, Bloomberg successfully sued the private press clubs of Japan, called kisha clubs, which had prevented it from reporting on the Japanese economy by denying access to the corporate press releases that often came as a benefit of membership. Today, he said, Bloomberg has 156 FOIA requests pending with the United States government.

Nevertheless, the Fed was not a kisha club, and November 2008 was not necessarily a moment to take an aggressive legal stance toward economic policy makers. Things were still quite raw: it had been only two months since the collapse of Lehman Brothers and only two weeks since the Dow Jones industrial average, already down some 2,200 points in seven sessions, dropped nearly 700 more in the opening moments of a single day.

But Mr. Winkler had already chosen to sue, and had so informed Daniel L. Doctoroff, Bloomberg’s president, and Peter T. Grauer, its chairman. Then, along with the outside law firm of Willkie Farr & Gallagher, he sought to write a document that would mirror in its language the vast sweep of recent economic events. Three days after the election of President Obama, his company filed a complaint that read, in part, “The documents that Bloomberg seeks are central to understanding the government’s response to the most cataclysmic financial crisis in America since the Great Depression.”

The complaint accused the Fed of failing to produce the documents and positioned Bloomberg, in a watchdog role, as “the eyes and ears of the public.” It concluded that disclosure of the documents was needed so that taxpayers could be “informed of how the Fed is safeguarding the public’s money.”