NEW YORK (TheStreet) -- Stocks extended deep losses on Friday afternoon as crude oil posteda big loss for the week.

The S&P 500 was down 1.2%, the Nasdaq slid 1.2%, and the Dow Jones Industrial Average fell 1%.

Oil prices continued to decline as West Texas Intermediate crude closes 0.6% lower to $48.14 a barrel and down 5.4% for the week. Prices dropped after the total number of active U.S. rigs drilling for oil climbed 21 to 659 over the week, according to Baker Hughes. Crude took a dive last week after six world powers agreed to a nuclear deal with Iran that would lead to Iranian oil on global markets.

Basic materials stocks were the worst performers on Friday. BHP Billiton(BHP) - Get Report, Rio Tinto(RIO) - Get Report, and Vale(VALE) - Get Report dropped, while the Materials Select Sector SPDR ETF (XLB) - Get Report fell 2.8%.

BlackBerry (BBRY) dropped nearly 4% after CEO John Chen said the results of a turnaround plan would likely be seen in the next 12 to 18 months. Chen had previously given the strategy a six-month timeline, which included a move to software and away from smartphones, for it to gain traction. 

Amazon(AMZN) - Get Report 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 10%.

Amazon's surge was countered by Biogen(BIIB) - Get Report which sank 21% 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) - Get Report and Cigna(CI) - Get Report 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) - Get Report 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) - Get Report spiked 4.8% 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) - Get Report climbed 1.8% 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) - Get Report 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) - Get Report 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.