* Sept factory activity down in US, China
* Oil prices fall 1 pct
* Apple down 2.1 pct; biggest drag on S&P, Nasdaq
* Dunkin falls after weak full-year forecast
* Indexes down: Dow 0.98 pct, S&P 0.72 pct, Nasdaq 0.86 pct (Updates to early afternoon)
By Abhiram Nandakumar and Tanya Agrawal
Oct 1 (Reuters) - Wall Street started the last quarter of the year in the red on Thursday as investors parsed mixed U.S. data and its implication for interest rates, and a rally in oil prices faded.
Oil prices fell as much as 1 percent on altered forecasts for the path of the latest U.S. hurricane, snuffing out an early rally that was prompted by fears the storm could damage U.S. East Coast oil installations.
Oil majors Exxon and Chevron were down about 1 percent.
Data on Thursday showed that the pace of growth at U.S. factories slowed in September, while new jobless claims pointed to a tightening labor market.
Earlier in the day, data from China showed factory activity fell again, but not as much as feared.
Mixed data could complicate the Federal Reserve’s plans to raise interest rates this year. All eyes will now be on the crucial non-farm payroll numbers due on Friday.
Investors will be keen to put the bruising quarter behind them and look ahead to the third-quarter earnings season, which begins next week.
Wall Street rallied on Wednesday as investors bought beaten-down stocks, with biotechs rising for a second day after a recent bout of sustained selling.
“Yesterday’s sell-up was in a vacuum. There is still a sell bias and the unrest around Syria and Russia are also weighing,” said Andrew Frankel, co-president of brokerage firm Stuart Frankel & Co in New York.
At 12:43 ET (1643 GMT), the Dow Jones industrial average was down 159.87 points, or 0.98 percent, at 16,124.83, the S&P 500 was down 13.81 points, or 0.72 percent, at 1,906.22 and the Nasdaq composite was down 39.64 points, or 0.86 percent, at 4,580.53.
All 10 major S&P sectors were lower, with the utilities index’s 1.8 percent fall leading the decliners.
Apple was down 1.3 percent at $108.92 on a report that chip suppliers were concerned the iPhone maker would cut chip orders for the fourth quarter. The stock was the biggest drag on the S&P and the Nasdaq.
Shares of Twitter were down 6.3 percent at $25.23, a day after on a report that co-founder and interim Chief Executive Jack Dorsey was expected to be named permanent CEO.
Dunkin Brands sank 10.5 percent to $43.85 after company gave weak full-year forecast and said it would shut 100 stores.
Declining issues outnumbered advancing ones on the NYSE by 1,935 to 1,037. On the Nasdaq, 1,830 issues fell and 832 advanced.
The S&P 500 index showed four new 52-week highs and 23 new lows, while the Nasdaq recorded 13 new highs and 142 new lows. (Reporting by Abhiram Nandakumar and Tanya Agrawal in Bengaluru; Editing by Saumyadeb Chakrabarty)