Check out which companies are making headlines before the bell:
Wal-Mart — Telsey Advisory Group upgraded the retail giant's stock to "outperform" from "market perform," saying the company appears to be regaining dominance in the physical retail market.
Twitter — The company refused a government order to reveal the name of a user with an anti-Trump account. Twitter has filed a lawsuit blocking that order, aimed at finding out who is behind the account that focuses on opposition to the president's immigration policies.
Alphabet — The company's YouTube unit unveiled a new policy that places ads on channels only after they reach 10,000 views. The move is aimed at preventing those who post unauthorized content from making money by doing so.
Yum Brands — The parent of KFC, Pizza Hut, and Taco Bell will cut the use of antibiotics in chickens bought for its KFC restaurants. The restaurant operator is giving poultry suppliers until the end of 2018 to stop using the antibiotics, joining McDonald's and Chick-fil-A and doing so among the biggest restaurant chicken sellers.
Southwest Airlines — The airline reported a March increase in revenue passenger miles of 3.9 percent compared to a year ago.
Twilio — The stock was upgraded to "overweight" from "neutral" at J.P. Morgan Securities, which said the cloud communications company has a number of unappreciated aspects. They include better valuation after the stock tumbled from its September highs, and the fact that Amazon's Web Services unit is increasingly using Twilio to power a number of its new products.
Amazon.com — Amazon will create 30,000 new part-time jobs over the next year, which would nearly double its U.S. part-time workforce. 25,000 of those will be in warehouses, while the rest will be home-based.
The Buckle — The stock was upgraded to "hold" from "sell" at Deutsche Bank, which said there is support for the apparel and accessories retailer's shares at current levels. Deutsche Bank did say it was still cautious about the company's long-term prospects.
Ruby Tuesday — The restaurant chain posted an adjusted loss of 6 cents per share as well as a same-restaurant sales drop of four percent. The company also named former Burger King and Cosi executive Jim Hyatt as its next chief executive officer.
Fiat Chrysler — The automaker's Chief Executive Sergio Marchionne will remain in that position until 2019, according to a report in an Italian daily financial newspaper.
WD-40 — WD-40 posted quarterly profit of 87 cents per share, three cents short of estimates, while revenue also fell short of forecasts. It also cut its sales guidance for the full year. The company said currency issues are masking the strength of its business.
PriceSmart — PriceSmart fell 2 cents short of estimates with quarterly profit of 90 cents per share, and the discount retailer's revenue also was less than analysts had expected.