Traders on the floor of the New York Stock Exchange.

Tyson Foods –The food producer earned 60 cents per share for the fiscal second quarter, missing estimates by three cents. Revenue, however, did exceed expectations, and the company said it is pleased with the quarter despite challenges posed by factors such as the severe winter weather.

Occidental Petroleum –The energy producer beat estimates by five cents with first quarter profit of $1.75 per share, excluding certain items, helped by the company's oil and gas operations.

Pfizer –The drug maker earned 57 cents per share, excluding certain items , for the first quarter, two cents above estimates. Revenue, though, fell short of consensus, as sales weakened in its two largest units. Separately, the company may need to raise its $106 billion offer for AstraZeneca by up to 10 percent, according to analysts. Pfizer's bids for the British drug maker have already been rejected three times.

Check out which companies are making headlines before the bell:

Zumiez–Piper Jaffray upgraded the retailer's stock to "overweight" from "neutral", based on factors such as the success of the company's streetwear-inspired fashions as well as cost cuts.

Salesforce.com– Deutsche Bank upgraded the stock to "buy" from "hold", saying it was now more comfortable with the company's handling of various ongoing issues. It also said valuation is reasonable following a 20 percent drop from the stock's highs.

Apple–The iPhone maker won a nearly $120 million award from Samsung in the month-long patent trial in California. However, that jury award was much less than Apple had sought.

JPMorgan Chase–The mega bank said its exposure to Russia amounted to $4.7 billion as of March 31, and that it is closely monitoring the events related to Ukraine and the impact of sanctions by the U.S. and other countries.

Microsoft–The software giant's biggest shareholder is now former CEO Steve Ballmer, rather than founder Bill Gates. An SEC filing shows that Gates sold 4.6 million Microsoft shares last week, dropping him to second behind Ballmer. Gates has been selling Microsoft shares regularly to fund his charitable foundation.

Sotheby's—Sotheby's has successfully held off an effort by Third Point's Daniel Loeb to remove the auction house's shareholder rights plan. A judge ruled Friday that he would not throw out Sotheby's "poison pill", which limits the amount activist investors can buy to 10 percent.

General Motors—GM is recalling nearly 52,000 SUV models because of a possibly inaccurate fuel gauge.

Electronic Arts–The game maker is reportedly close to an agreement with Comcast to stream games through Comcast's advanced X1 cable delivery system, according to Reuters.

Oracle– Bernstein upgraded Oracle to "outperform" from "neutral."

Chipotle Mexican Grill–Raymond James upgraded the restaurant chain's stock to "outperform" from "market perform."

—By CNBC's Peter Schacknow

Questions? Comments? Email us at marketinsider@cnbc.com