The financial crisis of 2008 was about home mortgages. Hundreds of billions of dollars in loans to home buyers were repackaged into securities called collateralized debt obligations, known as CDOs. In theory, CDOs were intended to shift risk away from banks, which lend money to home buyers. In practice, the same banks that issued home loans also bet heavily on CDOs, often using complex techniques hidden from investors and regulators. When the housing market took a hit, these banks were doubly affected. In late 2007, banks began disclosing tens of billions of dollars of subprime-CDO losses...
...After the housing crisis, subprime CDOs naturally fell out of favor. Demand shifted to a similar—and similarly risky—instrument, one that even has a similar name: the CLO, or collateralized loan obligation. A CLO walks and talks like a CDO, but in place of loans made to home buyers are loans made to businesses—specifically, troubled businesses. CLOs bundle together so-called leveraged loans, the subprime mortgages of the corporate world. These are loans made to companies that have maxed out their borrowing and can no longer sell bonds directly to investors or qualify for a traditional bank loan. There are more than $1 trillion worth of leveraged loans currently outstanding. The majority are held in CLOs.