 Investment banks (securities broker-dealers) held $33 billion (thousand million) in assets in 1978 (equivalent to 1.3% of U.S. GDP), but held $3.1 trillion in assets (equivalent to 22% U.S. GDP) in 2007.The securities that were so instrumental in triggering the financial crisis of 2007-2008, asset-backed securities, including collateralized debt obligations (CDOs) were practically non-existent in 1978.By 2007, they comprised $4.5 trillion in assets, equivalent to 32% of U.S. GDP.