IndyMac Bank

IndyMac's 2008 failure—the second-largest bank failure in US history at the time—demonstrates how mortgage concentration creates systemic fragility. The thrift originated $77 billion in Alt-A mortgages without verifying borrower income. When a senator's letter questioning the bank's stability triggered a run, IndyMac lost $1.3 billion in 11 days. Like a predator that overfed on toxic prey, IndyMac poisoned itself through its own appetite.