Check out which companies are making headlines before the bell:
Wal-Mart — Cowen upgraded the retail giant to "outperform" from "market perform," citing positive traffic trends and pricing among other factors. At the same time, Cowen downgraded Target to "market perform" from "outperform," saying it does not see catalysts to reignite growth in comparable sales and that recent changes are not resonating with customers.
Philip Morris International, Reynolds America — Goldman Sachs upgraded Philip Morris to "buy" from "neutral," and downgraded Reynolds to "neutral" from "buy." Goldman said overall, it's neutral on the tobacco sector, but has shifted its preference to Philip Morris from Reynolds. The firm said the bull case for Reynolds is largely played out after significant outperformance since it rated it a "buy" in June of 2015.
Finish Line — Deutsche Bank cut the athletic apparel and footwear seller to "hold" from "buy," primarily on a valuation basis after 34 percent run-up so far this year. It still sees good long-term performance for Finish Line, however.
Tesla — The automaker announced revisions to its Autopilot system. Tesla CEO Elon Musk said the changes add new safeguards to keep drivers engaged at higher speeds.
United Continental — United reported a 0.6 percent increase in revenue passenger miles for August compared to a year ago.
Alphabet, Sanofi — The two companies have formed a $500 million joint venture to focus on new solutions and treatments for diabetes. Sanofi will work with the Google parent's Verily life sciences unit.
Praxair — Praxair and Germany's Linde have ended merger talks, according to both industrial gas makers. The potential combination would have had a total value of more than $60 billion.
Taro Pharmaceuticals — Taro was subpoenaed by the U.S. Justice Department, along with two of its senior officers, in connection with a federal investigation into generic drug pricing.
Perrigo — Starboard Value took a 4.6 percent stake in the drug maker, according to the Wall Street Journal. The paper said the activist investment firm sent Perrigo a letter over the weekend saying it had failed to achieve performance targets and that it had been distracted fending off a takeover bid from Mylan in 2015.
Apple — Apple has scaled down its self-driving car project, according to a Wall Street Journal report, with several dozen employees being laid off. The paper points out that Apple has never publicly acknowledged working on a self-driving vehicle.
HP Inc. — HP will buy Samsung's printer business for $1.05 billion, with the deal expected to close within 12 months. Samsung will invest up to $300 million in HP as part of the transaction.
AstraZeneca — Jefferies raised its rating on AstraZeneca to "buy" from "hold," saying the potential of the drug maker's cancer drug portfolio is not fully reflected in the stock's price.
Lexmark — Lexmark's soon-to-be new owners, Apex Technology and PAG Asia Capital, are exploring the sale of the printer maker's software business, according to a Bloomberg report. The report said that business could fetch up to $1 billion.