Greenspan, 82, acknowledged that he had also been wrong in rejecting fears that the five-year housing boom was turning into an unsustainable speculative bubble that could harm the economy when it burst. Greenspan maintained during that period that home prices were unlikely to post a significant decline nationally because housing was a local market.
He said Thursday that he held to that belief because until the current housing slump there had never been such a significant decline in prices nationwide. He said the current financial crisis had "turned out to be much broader than anything that I could have imagined."
Greenspan was asked to defend a variety of actions he took as Federal Reserve chairman — resisting recommendations to use the Fed's powers to crack down on subprime mortgages, for one. And opposing efforts to impose regulations on derivatives, the complex financial instruments that include credit default swaps, which have also figured prominently in the current crisis.
He said that outside of credit default swaps, the bulk of financial derivatives had not caused major problems. He said the boom in subprime lending occurred because of the huge demand for investment opportunities in a global economy, and he blamed the crash on a failure by investors to properly assess the risks from such mortgages, which went to borrowers with weak credit.
As for firms that package mortgages into securities, he said, "As much as I would prefer it otherwise, in this financial environment I see no choice but to require that all securitizers retain a meaningful part of the securities they issue."
On the billions of dollars of losses suffered by financial institutions because of their investments in subprime mortgages, Greenspan said he had been shocked by the failure of banking officials to protect their shareholders from their bad loan decisions.
"A critical pillar to market competition and free markets did break down," Greenspan said. "I still do not fully understand why it happened."
Contributing: Associated Press