Seven Days That Shook Wall Street

It was the week that shook the financial world to the core. On Friday, Sept. 12, traders left the New York Stock Exchange for the weekend. But key banking officials, facing the impending failure of the venerable Lehman Brothers investment house and a shaky outlook for two other huge financial players—investment firm Merrill Lynch (MER) and insurance giant American International Group (AIG)—began a series of weekend meetings in an effort to prevent a possible collapse of the global financial system.

Over the next seven days, the nation's financial leaders, captained by Treasury Secretary Henry Paulson and Federal Reserve Chairman Ben Bernanke, produced a rapid succession of moves that reversed a decades-long trend toward financial deregulation and fundamentally changed the face of the American financial system. Lehman failed and Merrill was sold to Bank of America (BAC). The government took effective control of AIG in an $85 billion bailout. And, in the biggest intervention of all, officials proposed to purchase the troubled mortgage assets of financial firms, a move that could cost hundreds of billions of additional dollars.

Meanwhile, worried investors sent the stock markets into a dizzying ride of huge gains and losses.

Here's how the events unfolded:

Friday, Sept. 12: The trading week ends with the fate of 158-year-old Lehman Brothers in grave doubt. Its stock had fallen sharply due to fears over its financial condition. Paulson, Bernanke, and New York Fed President Tim Geithner begin a series of meetings in Lower Manhattan with top bankers in an effort to engineer a bailout of Lehman, which had bet heavily in the subprime mortgage market. Two possible buyers emerge: Britain's Barclays (BCS) and Bank of America.

Saturday, Sept. 13: Talks on a possible Lehman buyout continue. The would-be rescuers look to the government to take on some of the risk, as it did in the shotgun sale of Bear Stearns to JPMorgan Chase (JPM) in March and the effective nationalization on Sept. 8 of mortgage giants Fannie Mae (FNM) and Freddie Mac (FRE). Government officials hold fast that there will be no federal bailout. Talks are inconclusive.

Sunday, Sept. 14: The negotiators continue meeting, facing a deadline to act before Asian markets open for Monday morning trading. But government officials insist there will be no federal backing of a Lehman rescue. With no help from Washington forthcoming, Barclays—the only possibility left after Bank of America leaves the table—withdraws. Lehman is done for. Meanwhile, Merrill Lynch CEO John Thain, seeing the writing on the wall, arranges the sale of his company to Bank of America for about $50 billion. In one day, the fates of two storied companies are sealed.

Wall Street’s Perfect Storm