If there is one financial firm that remains inseparable from the real estate calamity of the last two years, it's Lehman Brothers. Today's shocker? Lehman's back in business, as an aggressive player in the post-crisis commercial real estate market. Remember that Lehman filed for Chapter 11 bankruptcy on September 15, 2008, marking the largest bankruptcy -- with $600 billion in assets -- in U.S. history. The firm's failure precipitated a stock market free fall and the Great Recession. After a restructuring, Lehman fired its senior banks and relegated its portfolio to mid- and junior-level employees. Now, thanks to its deep institutional knowledge and unique bankruptcy status, the new Lehman manages $14.4 billion in real estate securities.