Defendant's convictions and sentence for multiple charges related to mail fraud and securities fraud are affirmed, where the district court: 1) did not err in refusing to grant to defendant a new trial although the court notes a pattern of discovery abuses by government counsel; 2) did not err in considering an ex parte sealed document submitted by the government; 3) did not abuse its discretion by not instructing the jury on accomplice/informant testimony and on multiple conspiracies; and 4) did not improperly impose Sentencing Guidelines enhancements based on the amount of loss, the number of victims, and defendant's status as a registered broker/dealer at the time of the offenses.