The major averages opened higher to end the month and quarter but succumbed to selling pressure during the day following hawkish comments from a Fed official and a potential government shutdown in October.  The Dow Jones Industrial Average fell 158 points after rising over 200 points during the morning hours. The S&P 500 dropped 11 points or 0.27% to 4,288. The Nasdaq Composite actually rose 18 points or 0.14% to 13,219.

The averages initially rallied thanks to encouraging economic data in the form of personal consumption expenditures price index, which is the Federal Reserve's preferred inflation metric. The so-called core PCE, stripping out volatile food and energy prices, rose 0.1% in August and 3.9% annually. Economists polled by Dow Jones expected that the core PCE would advance 0.2% on a monthly basis and 3.9% year over year.

The S&P 500 finished the month down 4.9% and the quarter lower by 3.7%. The Nasdaq Composite was off 5.8% in September, and down 4.1% for the quarter. Both posted their worst months this year. The Dow notched a 3.5% decline this month and a 2.6% fall for the quarter.

The Dow and S&P 500 ended the week down about 1.3% and 0.7%, respectively. The Nasdaq Composite ended 0.06% higher.