Four men who allegedly made nearly $62 million by using insider information to trade Dell Inc. stock pleaded not guilty to conspiracy and securities fraud charges Tuesday.

Level Global Investors LP co-founder Anthony Chiasson; Todd Newman, a former portfolio manager at Diamondback Capital Management LLC; Jon Horvath, an analyst at Sigma Capital Management LLC; and Danny Kuo, a fund manager for Whittier Trust Co., were arrested Jan. 18. The ring reportedly involved five hedge funds and investment firms, according to the office of Manhattan U.S. Attorney Preet Bharara.

Jesse Tortora, formerly of Diamondback; Spyridon Adonakis, a Level Global analyst; and Sandeep Goyal, a former Dell employee turned analyst, already have been arrested and are cooperating with investigators.

Prosecutors allege that Goyal maintained close ties with Dell after leaving the company in 2006 and continued to receive insider information about the company’s financial results from a Dell employee. He then circulated this information to several hedge funds and one trust company, according to the New York Times.

Over the last five years, an extensive insider-trading probe by Bharara’s office and the Federal Bureau of Investigation has resulted in charges being brought against at least 64 people, more than 50 of whom have pleaded guilty or been convicted.

Read more about the case from Bloomberg.

Read the lawsuit here.