Traders on the floor of the New York Stock Exchange.

Boeing–The aerospace giant for the first quarter, 20 cents above estimates, with revenue also beating consensus. Boeing saw an improvement in profit margins on the commercial side, and also raised its earnings forecast for the full year.

Dow Chemical – Dow earned 79 cents per share for the first quarter, eight cents above estimates, with revenue falling a bit short of consensus. CEO Andrew Liveris told CNBC that "self-help" programs have streamlined operations and increased profit margins.

Procter & Gamble –The consumer products company earned $1.04 per share for its third quarter, three cents above estimates, though revenue was slightly short. P&G's results were helped by a drop in overhead costs, though P&G did cut its growth targets for the year.

Check out which companies are making headlines before the bell:

Delta Air Lines–The airline earned 33 cents per share, excluding certain items, for the first quarter, four cents above estimates. Delta canceled more than 17,000 flights during the quarter, resulting in $90 million in lost revenue.

TE Connectivity–The company formerly known as Tyco Electronics reported second quarter profit of 95 cents per share, excluding certain items, four cents above estimates. Its results were aided by higher profit margins, and stronger sales in its transportation and industrial segments.

Thermo Fisher Scientific–The maker of lab equipment earned first quarter profit of $1.53 per share, 13 cents above estimates. Revenue also beat Street consensus, thanks to acquisitions and growth in Thermo Fisher's other businesses.

Johnson Controls–The maker of automotive controls fell a penny shy of estimates with second quarter profit of 64 cents per share, though its quarterly profit was 59 percent higher than a year earlier.

AT&T–The telecom giant reported first quarter profit of 71 cents per share, beating estimates by a penny. Revenue got a boost from new pricing for wireless handsets, and the company also added a greater number of wireless subscribers than analysts had predicted.

Amgen–Amgen fell seven cents short of forecasts with first quarter profit of $1.87 per share, excluding certain items. Revenue also fell short of consensus for the biotech company, as sales of key products like Enbrel were weaker than expected.

Yum Brands–The parent of KFC, Pizza Hut, and Taco Bell registered a two cent beat with first quarter profit of 87 cents per share, excluding certain items. The restaurant chain's closely watched China sales rose 9 percent at stores open at least a year.

Intuitive Surgical–The company reported first quarter profit of $1.13 per share, well short of estimates of $3.28, with revenue falling short as well. The medical products maker cites significant declines in sales of its da Vinci robotic surgery devices.

Skechers–The footwear company swamped estimates by reporting first quarter profit of 61 cents per share, compared to forecasts of 33 cents. Revenue was also well above expectations, as sales were strong both in the U.S. and abroad.

VMWare–The software company reported first quarter profit of 80 cents per share, excluding certain items, one cent above estimates. VMW was able to attract more customers for its cloud services.

Plug Power–Plug is planning a secondary stock offering to raise capital, although the fuel cell technology company said the exact amount would depend on market conditions.

Sarepta Therapeutics–The drug maker also announced a secondary offering, planning to raise as much as $100 million. Underwriters will have a 30-day option to buy as much as $15 million more in shares.

Illumina–The company reported first quarter profit of 53 cents per share, nine cents above estimates, with revenue and its full-year forecast also above Street consensus. Chief executive officer Jay Flatley said customers are responding well to the company's new gene sequencing products.

Toyota–The automaker beat out General Motors in first quarter global sales, compared to 2.42 million for GM and 2.4 million for Volkswagen.

—By CNBC's Peter Schacknow

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