In September 2008, reporting that Constellation Energy had exposure to Lehman Brothers following that investment banking firm's bankruptcy filing, Constellation's stock went down 56% in the first day of trading, having started at $67.87. The massive drop in the company's stock price led the New York Stock Exchange to halt trade of Constellation. The next day, as the stock fell as low as $13 a share, the company announced it was hiring Morgan Stanley and UBS to advise it on "strategic alternatives" suggesting a buyout. While French power company Electricite de France, who already owned 9.5% of Constellation's shares, bid for the company, Constellation ultimately agreed to a buyout by MidAmerican Energy, part of billionaire Warren Buffett's Berkshire Hathaway company. However, on December 17, 2008, Constellation Energy canceled its merger with Berkshire Hathaway and opted to sell its nuclear energy assets to EDF.