 S&P had announced a negative outlook on the AAA rating in April 2011.The downgrade to AA+ occurred four days after the 112th United States Congress voted to raise the debt ceiling of the federal government by means of the Budget Control Act of 2011 on August 2, 2011.Later, the US Government commenced an investigation into S&P's role in the rating of several mortgage backed securities which played a role in the 2008 financial crisis.