Pershing Square Capital Management LP, which in December 2012 revealed a $1 billion bet against the weight loss and nutritional products company, said recent press reports that it was behind the lawsuit, or had sued Herbalife itself, were false.

It also said that despite what it called Herbalife's "misleading public suggestions," U.S. District Judge Dale Fischer in Los Angeles did not address whether Herbalife was an illegal pyramid scheme, as Ackman has contended.

Herbalife shares had closed at $34.43 on March 17, before reports of Fischer's decision began to surface, but rose 12.6 percent the next day and have continued to move higher.

In Friday afternoon trading, they were up $3.52, or 9.28 percent, at $41.46, on market speculation that Ackman had begun to cover his short position. Ackman has said many times that he expects Herbalife's share price to fall to zero.

Fischer had written that shareholders led by two pension funds did not show that questions raised about Herbalife by Ackman and various federal and state investigators showed that the company had fraudulently inflated its stock price.

Herbalife said on Wednesday it welcomed the dismissal, and added: "We are confident in the strong fundamentals of our business model and remain committed to helping people and communities improve their nutrition."

In its statement on Friday, Pershing Square said it believed the result of the various probes "will be that Herbalife will be shut down or will be required to modify its deceptive practices so substantially that the company will not be able to survive."

Fischer's decision is dated March 16.

Herbalife did not immediately respond to a request for comment on Pershing Square's statement.

(Reporting by Jennifer Ablan, David Gaffen and Jonathan Stempel in New York; Editing by Jeffrey Benkoe and Tom Brown)

By Jonathan Stempel and Jennifer Ablan