NEW YORK (Reuters) - A federal judge on Monday ruled against an effort by the U.S. Federal Reserve to block disclosure of companies that participated in and securities covered by a series of emergency funding programs as the global credit crisis began to intensify.

In a 47-page opinion, Chief District Judge Loretta Preska of the federal court in Manhattan said the central bank failed to show that disclosure would cause borrowers in the Federal Reserve System to suffer “imminent competitive harm,” by stigmatizing them for using Fed lending programs.

“The board essentially speculates on how a borrower might enter a downward spiral of financial instability if its participation in the Federal Reserve lending programs were to be disclosed,” she wrote. “Conjecture, without evidence of imminent harm, simply fails to meet the board’s burden.”

Monday’s ruling comes as lawmakers and investors demand greater disclosure in how the government manages a series of programs designed to lift the economy out of its deepest recession in decades.

The case arose when two Bloomberg News reporters submitted requests under the federal Freedom of Information Act (FOIA) about actions the Fed took to shore up the financial system in 2007 and early 2008, including an expansion of lending programs and the sale of Bear Stearns Cos to JPMorgan Chase & Co JPM.N.

After the Fed resisted the request, Bloomberg sued to compel disclosure.

Preska concluded the Fed “improperly withheld agency records in response to a FOIA request by conducting an inadequate search,” she wrote.

FOIA obliges federal agencies to make government documents available to the public, subject to various exemptions.

Bloomberg News and the Fed did not immediately return requests for comment.

The case is: Bloomberg LP v. Board of Governors of the Federal Reserve System, U.S. District Court, Southern District of New York (Manhattan), No. 08-9595.