Check out which companies are making headlines before the bell:
Travelers — The insurer earned $2.30 per share for the first quarter, missing estimates of $2.55 a share, but the miss was due entirely to casualty losses related to storms in Texas very late in the quarter. Revenue was above analysts' forecasts.
General Motors — The automaker earned $1.26 per share for the first quarter, coming in 25 cents a share above estimates, while revenue was also well above Street forecasts. GM was helped by a more favorable sales mix, selling more of its higher profit margin SUVs and crossovers.
Southwest Airlines — The airline came in 4 cents above estimates with adjusted quarterly profit of 88 cents per share, while revenue also beat forecasts. Southwest was helped by lower fuel prices and the ongoing revamp of its jet fleet.
Under Armour — The athletic apparel maker doubled estimates with quarterly profit of 4 cents per share, while revenue also beat Street estimates. Results were helped by strong apparel demand, as well as launches of new running and basketball shoes.
DR Horton — The home builder reported quarterly profit of 52 cents per share, 5 cents a share above estimates, while revenue also beat Street forecasts. The company also raised its profit margin guidance amid solid demand, with orders up 10 percent from a year ago.
PulteGroup — PulteGroup earned 24 cents per share for its latest quarter, 4 cents above estimates, with the home builder's revenue also exceeding forecasts. Net new orders were up 24 percent from a year earlier. Separately, founder Bill Pulte escalated his drive to oust CEO Richard Dugas, saying he would vote against the entire board at the home builder's annual meeting unless Dugas resigns immediately.
Stanley Black & Decker — The toolmaker came in 14 cents a share above estimates, with adjusted quarterly profit of $1.28 per share. Revenue beat estimates, as well. The company also raised its full-year forecast on stronger sales and a drop in restructuring costs.
American Express — The financial services giant reported quarterly profit of $1.45 per share, beating estimates by 10 cents a share. Revenue was slightly above expectations, as cardholder spending rose 6 percent.
Yum Brands — Yum earned an adjusted 95 cents per share for its latest quarter, 12 cents above estimates, with the restaurant chain's revenue essentially in line. The parent of KFC, Pizza Hut, and Taco Bell also raised its full-year profit outlook on faster sales growth.
Mattel — Mattel lost an adjusted 13 cents per share for its latest quarter, 6 cents a share wider than estimates, although revenue was above forecasts. The toymaker has been hit by a sales slump in its iconic Barbie line, as well as other brands.
Las Vegas Sands — Las Vegas Sands missed estimates by 18 cents a share, with adjusted quarterly earnings of 45 cents per share. The casino operator's revenue was also below Street forecasts. The company's results were hurt by weaker Las Vegas results, as well as the ongoing downturn in Macau.
Qualcomm — Qualcomm came in 8 cents a share above estimates, reporting an adjusted $1.04 per share profit for its latest quarter. Revenue for the quarter was above estimates, but its current-quarter earnings guidance was not. The chipmaker did say it would recognize more than $200 million in revenue for the current quarter following the resolution of a patent dispute with LG Electronics.
United Continental — United reported adjusted quarterly profit of $1.23 per share, 5 cents a share above estimates, while the airline's revenue was in line with forecasts. Guidance for the current quarter was downbeat, as passenger revenue miles are set to decline up to 8.5 percent on soft bookings.
Citrix Systems — Citrix trounced forecasts by 26 cents with adjusted quarterly profit of $1.18 per share, and revenue was well above estimates, as well. The business software maker also raised its full-year 2016 guidance. The company is benefiting from both cost cuts and improved software sales.
Apple — Apple pushed back its planned quarterly earnings release one day, because of a memorial service for Silicon Valley business leader Bill Campbell. Apple will now release its earnings next Tuesday, April 26.
Yahoo — Yahoo's potential sale of its core internet business continues to be in the spotlight, with Britain's Daily Mail now saying it may partner with other suitors for a bid, although it doesn't plan to make an offer on its own.
Sony — Sony cut its profit estimate for the fiscal year ending in March due to slowing global smartphone sales.
Wal-Mart — The retailer will cut three slots from its board of directors as of the annual shareholders meeting in June, shrinking the total size to 12 members. Jim Walton, the son of founder Sam Walton, is among those leaving the board, retiring after 11 years as a director.