The US housing bubble began in the late 1990s fueled by low interest rates, an expansion of subprime lending, and speculation. By 2006, housing prices collapsed as supply increased and interest rates rose. Mortgage loans were repackaged and sold globally through complex financial instruments, spreading risk but also multiplying problems. When housing prices declined, defaults increased threatening financial stability. The US government implemented a $700 billion bailout plan under both Presidents Bush and Obama to inject capital into banks and support the financial system.