In the wake of the financial crisis, the equilibrium real rate apparently fell well below zero because of numerous persistent headwinds.
These headwinds include tighter underwriting standards and restricted access to some forms of credit; the need for households to reduce their debt burdens; contractionary fiscal policy at all levels of government after the initial effects of the fiscal stimulus package had passed; and elevated uncertainty about the economic outlook that made firms hesitant to invest and hire, and households reluctant to buy houses, cars, and other discretionary goods.