Check out which companies are making headlines before the bell on Tuesday:
Pfizer - The drugmaker reported first-quarter profit of $0.54 per share, excluding certain items, one cent below estimates, with revenue also falling short. Pfizer also cut its full-year forecast below current consensus on lower-than-expected sales and a stronger dollar, which hurt overseas results.
Aetna - The insurance company reported first-quarter earnings of $1.50 per share, excluding certain items, 11 cents above estimates, though revenue was slightly short of estimates. Aetna raised its 2013 forecast, in part because of strong membership growth in its Medicare business.
Starwood Hotels & Resorts Worldwide - Starwood earned $0.76 per share for the first quarter, well above estimates of $0.53, while revenue was also above Street estimates. Starwood enjoyed higher room rates during the quarter, particularly in the North American market.
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Nuance Communications - The software company reported second-quarter profit of $0.34 per share, six cents below estimates, with revenue well short of predictions. That came as product and licensing costs rose, while sales fell.
Spirit Airlines - The discount carrier earned $0.45 per share for the first quarter, three cents above estimates, with revenue also coming in above consensus. Spirit increased both capacity and the percentage of seats filled during the quarter.
Pitney Bowes - The mail and document services provider reported first-quarter profit of $0.42 per share, excluding certain items, two cents below estimates. It also cut its dividend to 18.75 cents per share from 37.5 cents, as weaker demand for mail impacted its results.
The McGraw-Hill Cos. - McGraw-Hill reported first-quarter profit of $0.80 per share, seven cents above estimates, with revenue essentially in line with consensus.
Express Scripts - The company reported first-quarter profit of $0.99 per share, excluding certain items, two cents above estimates. Revenue also beat consensus, and the pharmacy benefits manager also raised its full-year forecast, as customers use more profitable generic drugs.
Buffalo Wild Wings - Buffalo Wild Wings earned $0.87 per share for the first quarter, 12 cents short of estimates. However, revenue beat forecasts, helping give the shares a boost. CEO Sally Smith said the restaurant chain has continued investing capital for future success, despite the challenge of escalating chicken wing costs.
Herbalife - Herbalife reported first-quarter profit of $1.27 per share, excluding certain items, 21 cents above estimates, with revenue in line with estimates. The nutrition products company also raised its full-year forecast, in the face of the ongoing controversy generated by investor Bill Ackman, who has called Herbalife a "pyramid scheme."
The Hartford Financial Services Group - Hartford earned $0.92 per share for the first quarter, excluding certain items, 10 cents above estimates. The insurer is in the midst of a restructuring that focuses on its core businesses such as property casualty insurance and group benefits.
Hertz Global Holdings - Hertz beat estimates by four cents a share with first-quarter profit of $0.21 per share, with revenue also beating consensus. The car rental company benefited from higher prices and good results from newly acquired Dollar Thrifty.
Safeway - The supermarket chain has named its company president, Robert Edwards, as chief executive officer, replacing the retiring Steven Burd.
NYSE Euronext - The exchange operator earned $0.52 per share for the first quarter, four cents below estimates, with revenue also short of consensus. The company is in the process of being acquired by IntercontinentalExchange in a deal worth $8 billion, pending shareholder approval in a June vote.
BP - BP reported first-quarter profit of nearly a billion dollars for the first quarter, beating analysts' forecasts. The results were helped by upbeat trading results and output from two new oil fields.
Sprint Nextel - Sprint is unlikely to get an improved takeover bid from Softbank, according to Softbank founder Masayoshi Son. SoftBank is currently offering $20.1 billion for 70 percent of Sprint, but is competing with Dish Network's $25.5 billion bid.
Domino's Pizza - The pizza chain earned $0.59 per share for the first quarter, excluding certain items, four cents above estimates. Domino's had strong sales results globally, as well as lower expenses during the quarter.
(Read More: See CNBC's Market Insider Blog)
—By CNBC's Peter Schacknow
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