"Because the authorized audio recording is entitled to copyright protection, and because the copyright claim is properly registered, I deny the motion in full," judge Alvin Hellerstein wrote in his decision.
Swatch, the world's number one watchmaker, accuses Bloomberg of divulging financial information discussed during a telephone conference on February 8, which it said was only for analysts and which court documents show it subsequently copyrighted.
"This meeting was reserved for financial analysts, and we had specifically forbidden them from recording the conversation," Swatch spokeswoman Beatrice Howald told AFP.
"The Bloomberg journalists not only recorded this telephone conference, but they also posted it on their website," she said.
In a statement, Bloomberg said that a company should disclose its financial information to the public.
"We believe that if a public company discloses financial performance information to a select group of analysts, that company has a responsibility to be transparent and provide that information to everyone," it said.
"The investing public has a right to know and we remain confident that when all the facts come out the court will agree that we acted fairly in doing so," Bloomberg added.
The two parties will go to court on September 16, the judge added.