US stocks had ended slightly lower on Tuesday as a decline in healthcare and biotech stocks offset gains in United Technologies and Verizon.
A 5.7 per cent drop to $140.64 in IBM also weighed on the market. The stock hit a five-year intraday low at $140.28 after it reported a bigger-than-expected decline in quarterly revenue and cut its full-year profit forecast.
The S&P healthcare sector fell 1.5 per cent, while the Nasdaq Biotech Index dropped 3.2 per cent. Concerns about drug pricing have hit biotech and other healthcare shares.
"You're seeing weakness in momentum names in general. Obviously the healthcare names are under pressure again, especially pharma companies. That further increases the pall over that sector," said Michael O'Rourke, chief market strategist at JonesTrading in Greenwich, Connecticut.
At the same time, O'Rourke said, investors seem to be buying more stable names such as Apple. Apple rose 1.8 percent to $113.77.
Stocks have mostly gained this month following a selloff in the third quarter, though concern about third-quarter earnings has added to caution.
Among companies beating analysts' expectations, United Technologies rose 3.9 per cent to $95.62, giving the Dow its biggest boost.
Verizon's shares were up 1.2 per cent at $45.24 after the largest US wireless service provider reported better-than-expected revenue and profit.
The Dow Jones industrial average fell 13.43 points or 0.08 per cent to 17,217.11, the S&P 500 lost 2.89 points or 0.14 per cent to 2,030.77, and the Nasdaq Composite dropped 24.50 points or 0.5 per cent to 4,880.97.
The S&P 500 is up 5.8 per cent so far in October.
Earnings for S&P 500 companies are expected to have fallen about 4 per cent in the third quarter, while revenue is expected to have declined 3.8 per cent, according to Thomson Reuters data.
Of the S&P 500 companies that have reported so far, roughly 40 per cent have beaten revenue expectations, below the long-term average, according to Thomson Reuters data.
Travelers rose 2.5 per cent to $108.95. The insurer's quarterly profit topped estimates, helped by higher underwriting gains.
Harley Davidson skidded 13.9 per cent to $48.25 after the motorcycle maker cut its full-year shipment forecast.
Shares of Tesla dropped 6.6 per cent to $213.03 in heavy volume. Consumer Reports magazine found that advanced fuel-saving technology and digital multimedia systems in vehicles including the Tesla Model S sedan are hurting reliability.
After the bell, shares of Yahoo were down 1 per cent at $32.50 as it reported a drop in quarterly revenue, while Intuitive Surgical was up 7.6 per cent at $508.70 percent after it posted a revenue increase.
During the regular session, advancing issues outnumbered declining ones on the NYSE by 1,888 to 1,170, for a 1.61-to-1 ratio on the upside; on the Nasdaq, 1,426 issues fell and 1,345 advanced for a 1.06-to-1 ratio favouring decliners.
The S&P 500 posted 24 new 52-week highs and 3 new lows; the Nasdaq recorded 66 new highs and 49 new lows.
About 6.0 billion shares changed hands on U.S. exchanges, below the 7.3 billion daily average for the past 20 trading days, according to Thomson Reuters data.