The stock market ended the week with a dreary performance as the S&P 500 (SPY) fell below its 100-day moving average, dropping 1.9 percent to 2,012.37 at 4 p.m. in New York and posting its worst performance since August.

The Dow Jones Industrial Average (DIA) sank 309.54 points or 1.8 percent to 17,265.21 and the Nasdaq Composite Index (QQQ) lost 2.2 percent, falling 4.1% for the week. About 8.3 billion shares traded hands on U.S. exchanges, 16 percent above the three-month average.

Friday saw key indices slip to fresh lows with the overnight session reacting to news that the People’s Bank of China was trying to push the yuan to a four-year low against the dollar (6.4553) and concerns about weakness in commodities.

Down Across the Board

All ten sectors ended the day in negative territory which was not surprising considering the uncertainty revolving around whether or not the Federal Reserve will announce the first fed funds rate hike since June 2006 in its next FOMC meeting to take place by the end of the month.

Kevin Kelly, the New York-based chief investment officer at Recon Capital Partners, “I think there’s a lot of uncertainty with global growth that is just factoring into the year-end positioning. We’ve seen a broad-based selloff today. There’s nowhere to hide out there and that’s why this is so brutal. It seems like a redux of August when the Chinese actually devalued their currency in anticipation of a Fed rate hike and stronger dollar.”

The Chicago Board Options Exchange Volatility Index surged to a two-month high Friday, reflecting increased anxiety amid speculation over the outcome of a possible shift in policy. The VIX jumped 26 percent to 24.39, the biggest gain since Aug. 24 and rising 65 percent for the week, also the most since last summer.