Dealing a further blow to the sliding US economy, its leading credit rating agency Standard & Poor’s has downgraded the country’s ‘AAA’ sovereign credit rating  to AA + .

The unprecedented move is likely to reduce the confidence of investors in US economy. The credit rating agency said in a statement that the fiscal plan which Congress and the Administration recently agreed to would fall short of what would be necessary to stabilize the government’s medium-term debt plans.

However, other prominent credit rating agencies – Moody’s Investors Service and Fitch Ratings reassigned the AAA credit ratings for the US economy even as President Barack Obama signed a bill to end the debt-ceiling crisis that pushed the Treasury to the edge of default.