In 1990, Enron's Chief Operating Officer Jeffrey Skilling hired Andrew Fastow, who was well acquainted with the burgeoning deregulated energy market that Skilling wanted to exploit. In 1993, Fastow began establishing numerous limited liability special-purpose entities, a common business practice in the energy industry. However, this also allowed Enron to transfer some of its liabilities so that they would not appear in its accounts, allowing it to maintain a robust and generally increasing stock price and thus keeping its critical investment grade credit ratings.