Observers and analysts have attributed the reasons for the 2001–2006 housing bubble and its 2007–10 collapse in the United States to "everyone from home buyers to Wall Street, mortgage brokers to Alan Greenspan". Other factors that are named include "Mortgage underwriters, investment banks, rating agencies, and investors", "low mortgage interest rates, low short-term interest rates, relaxed standards for mortgage loans, and irrational exuberance" Politicians in both the Democratic and Republican political parties have been cited for "pushing to keep derivatives unregulated" and "with rare exceptions" giving Fannie Mae and Freddie Mac "unwavering support".
