The iPhone maker's shares fell 2.1 percent to $115.99, moving firmly below their 200-day daily moving average, a key technical level closely watched by traders. The stock was also the biggest drag on the three major U.S. indexes.
The main S&P sectors were split in half in terms of gainers and losers - energy stocks led the gainers as oil bounced back, while utilities were the biggest losers.
Among other companies scheduled to release results are Dow component Walt Disney
With a bulk of the S&P 500 companies having reported results, investors are taking to the sidelines ahead of Friday's monthly jobs data.
The report is shaping up to be critical for the market as it can provide clues on the timing of a rate hike. The U.S. economy created 225,000 new jobs in July, according to economists polled by Reuters.
Wall Street ended lower on Monday as tumbling oil prices dragged energy shares to a three-year low and factory data from China raised concerns about the world's second-biggest economy.
In the United States, consumer spending recorded its smallest gain in four months, while the pace of growth in the manufacturing sector slowed in July.
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Soft data has prompted some investors to argue that the U.S. Federal Reserve might hold off on raising rates until December. After the Fed meeting last week, investors expected a rate increase in September.
The Fed, which has kept interest rates near zero for nearly a decade, has said it will raise rates only when it sees a sustained recovery in the economy.
Oil prices steadied but have fallen more than 20 percent over the last month, while copper - seen as a bellwether of global growth - nudged off a six-year low.
At 9:47 a.m. ET (1347 GMT) the Dow Jones industrial average was up 3.94 points, or 0.02 percent, at 17,602.14, the S&P 500 was up 0.81 points, or 0.04 percent, at 2,098.85 and the Nasdaq Composite was up 2.78 points, or 0.05 percent, at 5,118.16.
Valuations remain a concern. The S&P 500 is trading near 16.8 times forward 12-month earnings, above the 10-year median of 14.7 times, according to StarMine data.
Baxalta
CVS Health
Coach
Regeneron Pharmaceuticals
Advancing issues outnumbered decliners on the NYSE by 1,664 to 1,009. On the Nasdaq, 1,397 issues rose and 831 fell.
The S&P 500 index showed 14 new 52-week highs and six new lows, while the Nasdaq recorded 39 new highs and 38 new lows.