of Constellation Energy Group, and he was elected chairman of the board in July 2002. Shattuck's early tenure at Constellation was characterized by the objective of refocusing the company on the energy sector by taking actions such as laying off 10% of the company's workers and selling off the company's Boeing 747, transport tanker, real estate assets, and nursing home business. Over the same period, he reversed an existing plan to divide the company with the assistance of Goldman Sachs and restructured the company to force more accountability to management. In response to worsening conditions for American energy companies, Shattuck aimed to refinance Constellation's $5 billion debt load and secure more credit from banks allowing the acquisition of various weaker energy companies going into bankruptcy. Shattuck's decisions were widely considered to be painful at first, but ultimately necessary to turn around and grow Constellation. In the next few years, Shattuck expanded Constellation's operations in the financial sector, staking out large positions in energy commodity markets and complex derivative products financed by large, short-term loans. For instance, Shattuck led Constellation's activities in buying power from utility companies and reselling power to customers around the country in deregulated markets resulting in significant growth. In expanding Constellation's energy trading activities, Shattuck predicted that only energy companies, and not financial firms, could create a market for energy derivatives and risk management in the energy industry. While these operations contributed greatly to Constellation's profits over the period, they also increased the company's exposure to financial market developments. When credit ultimately dried up during the financial crisis, ratings agencies downgraded Constellation's debt and Constellation stock fell by 76% leading some to question whether Shattuck should continue to lead the company. Nonetheless, general sentiment on Constellation's board was "overwhelmingly" to keep him citing his "imperturbability" amid chaos. Over the following few years, Shattuck steered the company through the global financial downturn, securing funding from Berkshire Hathaway to keep the company afloat while avoiding a buyout from the same company, preserving the independence of Constellation. Finally in April 2011, Exelon corporation announced plans to acquire Constellation Energy. The planned merger drew negative reactions from some but was ultimately approved by regulators and completed in March 2012. After Exelon completed its acquisition of Constellation Energy, Shattuck assumed the new role of executive chairman. Shattuck retired from Exelon on February 28, 2013 but remained on the board as non-executive chairman.