After Herbalife's earnings conference call on Wednesday, hedge fund manager Bill Ackman told CNBC that if the company is serious about transparency it should start answering some of his questions.
"To date, they have yet to respond to one question," Ackman said.
On Tuesday, Herbalife reported fourth-quarter earnings and a 2013 outlook that topped analyst estimates.
(Read More: Herbalife Earnings and Outlook Top Forecasts)
Ackman, who has taken a $1 billion short position in the nutritional supplement maker, is battling billionaire investor Carl Icahn who holds a nearly 13 percent long position.
(Read More: Icahn, Ackman in Epic Showdown of Billionaires)
On a conference call earlier Wednesday, Herbalife CEO Michael Johnson said he has had "short discussions" with Icahn but there was "nothing concrete to report."
Herbalife also plans to provide greater disclosure around it's distributor model, which has been subject of criticism from investors like Ackman. The company will also hire a head of research to better understand the motivation behind purchases, the company said on the call.
Later, Ackman said: "If Herbalife really wants investors to understand their business better and provide full transparency as Johnson said on the call, they should start by answering even one of the 284 questions we submitted publicly to them two weeks ago."
Click here for the latest Herbalife quote.