The benchmark S&P 500 fell below the 3,900 mark at the open on Friday, breaching a level that traders considered as a key support, after a profit warning from delivery firm FedEx spooked investors already concerned about aggressive rate hikes.
The benchmark index is now 5.8 percent above its mid-June closing low as a summer rally in Wall Street continues to unravel amid fears of steep increases in U.S. interest rates and deterioration in earnings growth.
