The subprime mortgage crisis began in 2007 when defaults rose sharply on subprime loans. This triggered a liquidity crisis wherein interbank lending froze up. Losses then spread from mortgages to other asset classes as mortgage-backed securities declined in value. The crisis had wide-ranging effects, including a severe global recession, a housing market decline, and banks and financial firms failing or needing government assistance. The document discusses the chronology of events leading up to the crisis as well as its causes such as conflicts of interest in the ratings and securitization processes, and effects such as the recession and housing market collapse in the US.