Massachusetts Senator Edward Markey is asking for more information about the business practices of nutrition company Herbalife, which has been accused of running a pyramid scheme by prominent hedge fund manager William Ackman.

Markey sent letters to the Securities and Exchange Commission, the Federal Trade Commission and to Herbalife itself to try an obtain more information, his office said in a news release on Thursday.

Herbalife shares fell as much as 13% on the news. (What's the stock doing now? Click here)

"There is nothing nutritional about possible pyramid schemes that promise financial benefit but result in economic ruin for vulnerable families," Markey said in a statement.



The company told CNBC it had received Markey's letter and was planning to address his inquiries.

—Reuters with CNBC.com

