On March 7, the American credit rating agency Moody's Investors Service downgraded the credit rating of Greek sovereign debt to B1, marking the start of the European sovereign debt crisis and worsening the economic situation in the eurozone. The crisis sparked changes of government in the worst-hit countries, including Ireland, Portugal, Greece, Italy and Spain.
In August, the U.S.-based financial services company Standard & Poor's downgraded the credit rating of American long-term sovereign debt to AA+. It was the first time the United States lost its AAA credit rating.
With the world economy staggering under the European and U.S. debt crises, the Occupy Wall Street movement was launched on Sept. 17 protesting corruption and greed in the financial sector. The movement later spread to many cities and towns in the United States and other Western countries, and has triggered social crises in these countries.