NEW YORK: Galleon hedge fund founder Raj Rajaratnam and co-defendant Danielle Chiesi asserted their innocence on Monday to charges of securities fraud, in what US prosecutors describe as the biggest hedge fund insider trading case ever.

Wearing a crisp black suit and blue tie, Rajaratnam, 52, betrayed no emotion as he entered a plea of not guilty before Judge Richard Holwell at US District Court in Manhattan. Chiesi, 44, who also entered a not guilty plea, smiled and embraced her mother following the proceeding.

Her mother, Gloria Chiesi, afterward told reporters: "My daughter is innocent and that's what you will be printing. She's my angel. God borrowed my body and gave me this girl."