NEW YORK (TheStreet) -- Stocks extended losses by mid-morning Friday as general market malaise hung over Wall Street. Investors have been wary this week as earnings reports from industry bellwethers such as Apple (AAPL) and Caterpillar (CAT) fell short of estimates.

The S&P 500 was down 0.36%, the Nasdaq slid 0.15%, and the Dow Jones Industrial Average fell 0.33%.

Amazon  (AMZN) was one of the few bright spots on markets Friday after blowing past quarterly estimates. The e-commerce giant earned 19 cents a share while analysts expected a loss of 14 cents. Sales climbed nearly 20% to $23.18 billion, ahead of estimates of $22.39 billion. The better-than-expected quarter was tied to strong sales in North America and growth in Prime subscriptions. Shares surged more than 14%.

Amazon's surge was countered by Biogen (BIIB) which sank 16% after lowering full-year guidance. The biopharmaceutical company anticipates 2015 revenue growth between 6% and 8%, down from previous growth estimates of 14% to 16%.

Anthem (ANTM) and Cigna (CI) slipped after announcing a merger deal Friday following a month of reports. Indianapolis-based Anthem will acquire health insurance company Cigna for $54.2 billion, a deal that values Cigna shares at $188 a share. Cigna and Anthem shares fell more than 2%.

In other earnings news, Starbucks  (SBUX) earned 42 cents a share, a penny above estimates, while revenue climbed nearly 18% to $4.88 billion. Global traffic increased 7% compared to expectations of 6.2%. The stock rose more than 3%.

Visa (V) spiked 6.4% after beating analysts' estimates on the top- and bottom-lines. The credit card company earned 74 cents a share, beating expectations by 15 cents, while sales surged 11.4% to $3.52 billion. Payments volume increased 11% on a constant-dollar basis.

Xerox (XRX) climbed 2% after the printing company reported a mixed quarter. Earnings of 22 cents a share were in-line with expectations, while sales of $4.59 billion fell 7.1% from a year earlier and missed by $50 million.

American Airlines (AAL) reported record profit in its second quarter. Adjusted net income of $2.62 a share beat estimates by 2 cents. Total revenue passenger miles climbed 1.1% over the quarter.

AT&T (T) received final regulatory approval for its $48.5 billion acquisition of DirecTV (DTV), according to Reuters. The Federal Communications Commission likely will announce the results of their vote on Friday. AT&T and DirecTV shares were up more than 2%.

U.S. insurance company StanCorp Financial Group (SFG) shot nearly 50% higher on news Japanese firm Meiji Yasuda Life Insurance would acquire it for 600 billion yen ($4.8 billion).

Sales of single-family new homes in the U.S. fell 6.8% to an annual rate of 482,000 in June, its slowest pace in seven months. Economists had expected a reading of 550,000. New home sales in May were revised down to 517,000 from an original reading of 546,000.

China's Shanghai Composite closed 1.3% lower after manufacturing activity shrank at its fastest pace in 15 months in July. The Caixin-Markit Flash Manufacturing PMI dropped to 48.2 in July from 49.4 in June. Economists had expected the measure to increase to 49.7.

European markets traded mixed after eurozone business activity disappointed at the beginning of the second half of the year. Eurozone PMI fell to 53.7 in July, down from a four-year high of 54.2 in June. Eurozone economies remained in expansion territory, save for French manufacturing which dipped into contraction with a 49.6 reading.