Check out which companies are making headlines before the bell:

AutoZone — The auto-parts retailer posted better-than-expected quarterly earnings and revenue, sending its stock nearly 7 percent higher in premarket trading. Same-store sales — a key metric for retailers — rose 2.3 percent in the quarter, also surpassing estimates.

Toll Brothers — Toll Brothers reported weaker-than-forecast earnings and sales, pushing its stock 6.3 percent lower before the bell. The company said in its fourth-quarter report that its results were hurt by higher labor and raw material costs. Toll also said it experienced the slowest orders growth in six quarters.

Ford Motor — Ford said it will launch 50 new vehicles in China by 2025, including 15 electric vehicles, in an effort to boost slowing sales.

McDonald's — Analysts at Jefferies upgraded the fast-food giant's stock to buy from hold and hiked their price target to $200 a share from $50. In a note to clients, they said McDonald's "use of data and technology … should attract a higher multiple over time, while leading to higher returns." McDonald's shares closed Monday's session at $170.65.

Snap — The social media company's stock was upgraded to overweight from equal weight by analysts at Barclays. The analysts see revenue upside for Snap in the fourth quarter and believe the company's pricing transition will be "in the rear-view mirror" next year. Barclays also raised its price target on Snap to $18 a share from $11. The stock finished at $13.57.

Humana — The health insurance giant said it expects Medicare Advantage membership to approach the higher end of its growth range by the end of 2018, according to an 8-K filing released Tuesday.

SL Green Realty — The real estate trust's stock was upgraded to buy from neutral by analysts at BTIG, who noted the company has "proven its ability to win in a challenging NYC office market." The analysts also raised their price target on SL Green's stock to $122 a share.