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While the housing and credit bubbles were building, a series of factors caused the financial system to both expand and become increasingly fragile, a process called financialization. U.S. Government policy from the 1970s onward has emphasized deregulation to encourage business, which resulted in less oversight of activities and less disclosure of information about new activities undertaken by banks and other evolving financial institutions. Thus, policymakers did not immediately recognize the increasingly important role played by financial institutions such as investment banks and hedge funds, also known as the shadow banking system. Some experts believe these institutions had become as important as commercial (depository) banks in providing credit to the U.S. economy, but they were not subject to the same regulations.

What institutions comprise the shadow banking system?
investment banks and hedge funds