Frank Quattrone, the former Credit Suisse First Boston technology investment-banking guru, reportedly pleaded not guilty Tuesday to charges of obstruction of justice and witness tampering. Prosecutors alleged that Quattrone directed CSFB employees to destroy documents subpoenaed by a federal grand jury and the SEC, according to a Reuters report. The SEC was looking into how CSFB allocated shares of hot stock offerings in the 1990s. Quattrone told Judge Richard Owen that he understood the charges, and he entered a plea of not guilty, according to Reuters. The trial is scheduled for late September, the report said. Quattrone declined to comment after the hearing, according to the report.