Global rating agency, Fitch Ratings has said that it has kept the top level credit rating of AAA for the United Sates unchanged.

The company also said that it holds the outlook for the world's largest economy at negative citing debt levels that could expose the country to higher risks if the authorities do not take steps to reduce deficit. IT said in a statement that the top rating of AAA shows strong economic and credit fundamentals of the American Economy.

There are concerns that the Federal Reserve might halt its stimulus package and this might hurt growth. However, officials are trying to calm the situation by convincing investors that the Federal Reserve will not suddenly withdraw stimulus package that has helped the US economy survive the financial crisis by keeping the borrowing costs low. The reserve will continue to provide stimulus to support the recovery of the economy but has indicated that it will begin a gradual roll back.

Fitch that the federal budget deficit has fallen to levels that are consistent with the debt stabilization. It said that it will conduct a review of the rating this year. "The outlook remains negative due to continuing uncertainty over the prospect for additional deficit-reduction measures necessary, over the medium to long term," Fitch said.

Tesco started focusing at the UK market with an investment of $1.6 billion to boost its business in the country after it faced criticism that its international expansion in the US has not been successful. Some believe that German discount supermarket chain, Aldi Group might be interested in acquiring entire or parts of Fresh & Easy food shops business in the US from Tesco.