What is the main conflict in The Big Short: Inside the Doomsday Machine by Michael Lewis?

The Big Short: Inside the Doomsday Machine by Michael Lewis is a return to Lewis' financial roots. In this book, Lewis explores the stock market crash of 2008. Lewis examines the bond market and the move into subprime mortgage bonds that led to the crash that actually took place over the long months in 2007 when the housing prices suddenly dropped nationwide. In this character driven narrative, Lewis examines the group of people who saw the crash coming and either kept quiet to protect potentially large investments or were too shocked to speak up.