The former chief executive of the failed brokerage firm Peregrine Financial Group, who last month wrote a note admitting that he had committed a long-ranging investment fraud, pleaded not guilty on Friday to lying to federal regulators, the New York Times Deal Book Blog reported. Federal prosecutors charged Russell Wasendorf Sr., the former head of Peregrine, with 31 counts of deceiving regulators about the value of his customers' accounts. If convicted, he would face a maximum prison sentence of 155 years.