Correction, 6/7/13, 3:50 p.m. EDT: The print version of this story included an incorrect figure for the aggregrate decline in The Am Law 200′s cost base in 2009. The correct figure is $2.4 billion. The fourth paragraph of this story has been revised to reflect the correct figure. We regret the error.

September 15, 2008: The day everything changed. In the early hours of the morning, while most of America slept, investment bank Lehman Brothers Holdings Inc. filed for Chapter 11 protection. The U.S. economy was already reeling from the collapses, one week prior, of government-sponsored mortgage buyers Fannie Mae and Freddie Mac, which collectively owned or backed the majority of the country’s $12 trillion mortgage market. Lehman’s bankruptcy, which remains the largest in U.S. history, and the subsequent bailout of insurance giant American International Group Inc. the very next day, was enough to send the financial markets into full-blown meltdown. The impact on the country’s top law firms was profound.