On September 2008 Lehman Brothers filed for bankruptcy and the world became aware that the financial crisis that had been unfolding for months was far more serious than expected. Months later it became clear that the financial crisis of 2008-2009 was the worst economic downturn since the Great Depression of the 1930s: real GDP in the United States declined at an annual rate of 1.3% in the fourth quarter of 2008 5.4% in the first quarter of 2009 and 6.4% in the second quarter of 2009. The crisis originated in the U.S. but it spread rapidly to the rest of the world as real world GDP fell by 6.4% in the fourth quarter of 2008 and by 7.3% in the first quarter of 2009.