A U.S. judge refused on Tuesday to dismiss an insider-trading charge against former Bear Stearns hedge fund manager Ralph Cioffi, court documents showed.

Judge Frederic Block of the U.S. District Court for the Eastern District of New York denied Cioffi's motion, according to the minutes of the hearing posted on the court's website.

Prosecutors allege that Cioffi transferred a portion of his own holdings from a fund without telling investors.

A lawyer for Cioffi could not be immediately reached for comment by Reuters.

Former fund managers Cioffi and Matthew Tannin are set to go on trial in September on criminal charges that they defrauded investors at two mortgage-linked funds that collapsed in 2007.

The 2007 collapse of the High Grade Structured Credit Strategies Master Fund and the Enhanced Master Fund, was one of the first signs of major financial trouble at Bear Stearns, which was sold to JPMorgan Chase & Co in an emergency deal brokered by the U.S. Federal Reserve in March 2008.

The U.S. Securities and Exchange Commission also has filed civil securities fraud charges against the two men.

(Reporting by Ajay Kamalakaran in Bangalore)