Several former insiders allege that Enron inflated the value of its investment portfolio using the following tricks. The company declined to comment.BOGUS VALUATIONS

Ex-employees say the value of Enron's stake in private deepwater driller Mariner Energy ballooned by using overly generous assumptions about potential reserves and long-term oil-and-gas prices.DISCARDED CONTROLS

The Risk Assessment & Control unit was supposed to be able to modify investment valuations it felt were too high. But insiders say top brass often ignored RAC's financial analyses.