Enron rose rapidly in the 1980s and 1990s through aggressive accounting practices and trading of energy contracts. However, by 2001 it began collapsing under the weight of hidden debts and losses, revealed through the use of special purpose entities and misleading financial reports approved by its auditor, Arthur Andersen. The bankruptcy of Enron in late 2001 resulted in billions lost for investors and employees and led to reforms through the Sarbanes-Oxley Act to increase transparency in corporate accounting.