This case examines the causes and consequences of the Lehman Brothers bankruptcy during one of the most fascinating weekends in financial history. It's about the commercial paper market, a major funding market served by Lehman Brothers, and the events that led to "breaking the buck" on money market funds. It also examines the CDS market where Lehman was such a big player, the potential impact that CDSs had on the crisis, and the notion and validity of the too-big-to-fail hypothesis.