Check out the companies making headlines before the bell:

Tesla – Tesla coverage has been resumed at Goldman Sachs with a "sell" rating. Goldman had removed its rating and price target on the automaker's shares last month after saying it was advising Tesla on CEO Elon Musk's go-private proposal, which has since been abandoned. Goldman also set a $210 price target, compared to its prior target of $195.

Verizon – Verizon was downgraded to "equal-weight" from "overweight" at Barclays, which likes the company's prospects but feels its current valuation puts a cap on the stock's potential upside moves.

Facebook – Moffett Nathanson downgraded the social media giant's stock to "neutral" from "buy," based on its view that revenue growth is slowing and that Facebook's long term profit margin guidance does not provide a case for the stock's long term outperformance.

Dollar Tree – Dollar Tree was downgraded to "outperform" from "top pick" at RBC Capital Markets, which cited a variety of issues at the discount retailer's Family Dollar unit.

WPP – WPP said profitability would decline this year, in the first earnings presented by new Chief Executive Officer Mark Read. However, Read – who was named CEO on Monday – also said the ad agency had seen revenue growth for the first time in a year.

United Parcel Service – UPS was upgraded to "strong buy" from "market perform" at Raymond James, which said the market is underappreciating the company's earnings and free cash flow outlook.

Nike – Nike is featuring Colin Kaepernick in a new ad campaign, as it begins celebrating the 30th anniversary of its "Just Do It" campaign. Kaepernick was the first NFL player to kneel during the national anthem as a form of protest.

Nordstrom – The retailer's stock was rated "buy" in new coverage at Goldman Sachs, which points to Nordstrom's operation of both a full-price business with premium offerings as well as an off-price format. In the same report, Goldman also gave "buy" ratings to retailers Kohl's and TJX.

JD.com — CEO Richard Liu has returned to China, days after being arrested in Minneapolis on suspicion of criminal sexual assault. The China-based e-commerce company said the accusation against Liu was unsubstantiated, and he was released without charges or bail.

Seagate Technology, Western Digital – Evercore downgraded both hard disk drive makers, lowering Seagate to "underperform" from "in line" and Western Digital to "in line" from "outperform." Pressure on flash memory pricing is mentioned as a key factor in the downgrades.

Sanofi – The French drugmaker received European Union approval for its treatment for a rare blood-clotting disorder. The U.S. Food and Drug Administration is expected to do the same early next year.

Las Vegas Sands, Wynn Resorts – The casino operators are on watch following the release of August gaming figures from Macau, which showed gambling revenue up 17 percent in the Chinese territory compared to a year earlier. That marks the 25th straight month of gains.

Novartis – The Swiss drugmaker unveiled plans to streamline worldwide drug production. The move is designed to boost profit margins in order to counteract falling drug prices in the United States.

Amazon.com – Amazon is challenging Facebook and Alphabet's Google unit in online advertising, according to The New York Times. The paper said Amazon's data on people's shopping habits gives it the ability to place ads more effectively.

Roku – Roku was rated "buy" in new coverage at Guggenheim, which calls the maker of video streaming devices a key player in the disruption of the domestic television business.