[NEW YORK] US stocks started the fourth quarter on a subdued note, weighed down by healthcare and consumer stocks.
The S&P 500 healthcare index fell 0.7 per cent, the most among the 10 major S&P indexes that were lower, due to declines in Pfizer and Merck.
Consumer staples fell 0.59 per cent, dragged down by Procter & Gamble and PepsiCo.
The Purchasing Managers' Index (PMI) from the Institute of Supply Management is expected to show that factory activity expanded in September after having contracted in August.
Investors are also on the lookout for news from Deutsche Bank, which is working to reach a settlement with US authorities who have demanded a fine of up to US$14 billion from the bank for mis-selling mortgage-backed securities.
While the bank's Frankfurt-listed stock was not trading due to a public holiday, its US-listed shares were down 1.2 per cent at US$12.96 on Monday.
The travails of Germany's biggest lender has unsettled investors who are now awaiting third-quarter corporate earnings and the upcoming US presidential election.
"It looks like a quiet start to the day and that's not surprising," said Art Hogan, chief market strategist at Wunderlich Equity Capital Markets in New York.
"It's a back-end loaded week with jobs numbers on Friday, but if we get a positive read on ISM manufacturing, we could say that August was a blip and that will be constructive for the markets today."
A report on monthly hiring activity on Friday will be assessed by investors as it will play a big role in the Federal Reserve's decision on raising interest rates this year.
At 9:37 am ET (1337 GMT), the Dow Jones Industrial Average was down 79.3 points, or 0.43 per cent, at 18,228.85.
The S&P 500 was down 7.33 points, or 0.34 per cent, at 2,160.94 and the Nasdaq Composite was down 8.31 points, or 0.16 per cent, at 5,303.69.
Tesla shares rose 2.3 per cent to US$208.82 after the electric carmaker said third-quarter deliveries rose by 70 per cent to 24,500 cars.
Janus Capital soared 17 per cent after the asset manager said it had agreed to an all-share US$6 billion merger with London-listed rival Henderson Global.
Cabela's surged 14.5 per cent to US$62.90 after the company said it would be acquired by Bass Pro Shops in a deal valued at about US$5.5 billion.
Declining issues outnumbered advancing ones on the NYSE by 1,585 to 1,038. On the Nasdaq, 1,343 issues fell and 936 advanced.
The S&P 500 index showed two new 52-week highs and three new lows, while the Nasdaq recorded 23 new highs and seven new lows.