Stocks were at session lows by late morning Friday as Apple (AAPL - Get Report)  suffered its worst three-day stretch since early 2013. 

The S&P 500 was down 0.65%, the Dow Jones Industrial Average fell 0.64%, and the Nasdaq slid 0.8%.

Apple fell more than 2%, on track for its worst close since mid-2014, as sentiment on the tech giant shifted. Earlier in the week, the world's largest company reported its first revenue decline in 13 years. On Thursday, billionaire investor Carl Icahn disclosed he no longer had any stake in the company. Shares have fallen 11% since Monday. 

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Gilead Sciences (GILD - Get Report)  lagged the health sector sector, tumbling 7% after quarterly revenue missed expectations. The drugmaker reported first-quarter revenue of $7.8 billion, 2.6% higher than the year-ago quarter but below estimates of $8.06 billion. Adjusted earnings of $3.03 a share came in below expectations of $3.15 a share.

Major health care stocks including Merck (MRK - Get Report) , UnitedHealth Group (UNH - Get Report) and Biogen (BIIB - Get Report) were all lower, while the Health Care Select Sector SPDR ETF (XLV - Get Report) slid 1.8%. 

A monthly reading on consumer activity in the U.S. showed a tendency to save instead of spend. Consumer spending rose just 0.1% in March, according to the Commerce Department, half what economists had expected. Incomes continued to march upward, notching a 0.4% increase last month. The savings rate rose to 5.4% from 5.2%, its highest level since late 2012.

Economic activity in the Chicago area came in weaker in April as a weaker global economy tempered demand for U.S. products. The Chicago PMI fell to 50.4 in April, just above the level that separates expansion from contraction. A measure of new orders fell to its lowest level since December. 

Consumer sentiment fell in the final reading for April from the University of Michigan as Americans grew more concerned over future economic conditions. The sentiment index fell to 89 from 91, below estimates of 90. The future expectations measure fell 4.8% over the month to 77.6. Current views of the economy remained positive, rising 1% to a reading of 106.7. 

"Despite a welcome rise in income, consumer spending remains tepid, boosting savings rather than topline activity with the weakest first-quarter growth rate in two years," said Lindsey Piegza, chief economist at Stifel. "Even the most recent boost to wages appears to be too little, too late after years of stagnant income growth as consumers now look at the latest bounce with skepticism."

Crude oil was trading around 2016 highs on Friday morning, buoyed by a report from the U.S. Department of Energy that showed a decline in domestic output. However, upward momentum could be capped after Deutsche Bank analysts warned an impending rise in production from the Organization of the Petroleum Exporting Countries could prevent further rallies.

"A sustainable rise in OPEC production may be just around the corner, and ... the rally may pause," Deutsche Bank analysts said.

West Texas Intermediate crude oil was trading 0.2% higher at $46.12 a barrel on Friday morning.

Exxon Mobil (XOM - Get Report) was slightly higher after beating low-bar quarterly estimates. Net earnings of 43 cents a share were sharply lower than $1.17 a year earlier. Analysts had expected profit of 31 cents a share. Strength in Exxon's chemicals business helped to offset weakness in its energy business.

Fellow oil producer Chevron (CVX - Get Report) fell 1.3% following a disappointing quarter. A loss of 39 cents a share was wider than an expected loss of 17 cents. Revenue of $23.55 billion came in below estimates of $24.5 billion. Energy companies have been under pressure as crude oil suffers a prolonged period of low prices.

Rovi ( ROVI) announced Friday it reached an agreement to buy TiVo ( TIVO - Get Report) for around $1.1 billion in a cash-and-stock deal. The per-share bid of $10.70 marks a 14% premium to TiVo's Thursday close. The companies expect annual cost synergies of at least $100 million.

Amazon (AMZN - Get Report) soared 10% after returning to a profit in its first quarter. The e-commerce giant earned $1.07 a share in its recent quarter compared to a loss of 12 cents a year earlier. Analysts expected per-share earnings of 58 cents. Amazon also forecast second-quarter sales between $28 billion and $30.5 billion, above consensus of $28.3 billion.

LinkedIn (LNKD) jumped 3% after topping earnings estimates for its first quarter. The professional social network earned an adjusted 74 cents a share, better than an expected 60 cents a share. Revenue jumped 35%.

Groupon (GRPN - Get Report) fell 15% after quadrupling quarterly losses on increased promotional expenditures. The online discounts site expects its marketing efforts to begin reaping rewards in 2017. Groupon reported a loss of 8 cents a share compared to a year-earlier loss of 2 cents. An adjusted loss of 1 cent a share compared to profit of 3 cents in the year-ago quarter.

Caterpillar (CAT - Get Report) was on watch after announcing plans to shutter five U.S. plants, eliminating around 820 jobs. The construction machinery maker has been forced to reduce production in the face of weaker demand.