 For example, in June 2007, ratings agencies downgraded over 100 bonds backed by second-lien subprime mortgages.Soon after, the investment bank Bear Stearns liquidated two hedge funds that had invested heavily in mortgage-backed securities (MBS) and a few large mortgage lenders filed for Chapter 11 bankruptcy protection.Strains in interbank lending markets became apparent on August 9, 2007, after BNP Paribas announced that it was halting redemptions on three of its investment funds.