It revealed illegal behavior (B). Charges against Enron employees and its auditors included securities fraud, bank fraud, money laundering, conspiracy, insider trading and obstruction of justice.
The conviction of the auditors, Arthur Anderson, was eventually overturned by the Supreme Court, but by then the firm had gone out of business.
In addition to the illegal activity, many of the accounting treatments were considered unethical, but not necessarily illegal. These included the use of special purpose entities and recording trading transactions on a gross basis. It is estimated that Enron's shareholders lost a total of about $74 billion as a result of the scandal and ultimate demise of the company.