The US stock market begins the trading week as a result of Moody's downgrading of the US credit rating.
In early trading, the broad S&P 500 index falls 0.8 percent and the technology-heavy Nasdaq index loses 1.1 percent. The Dow Jones industrial index falls 0.5 percent.
On Friday, Moody's downgraded the rating from AAA to Aa1. A similar downgrade has previously been made by Moody's competitors Fitch Ratings and S&P Global Ratings. This means that the world's largest economy has fallen from the highest credit rating.
