Check out which companies are making headlines before the bell:

Tiffany — The luxury goods retailer reported a third-quarter profit of 80 cents per share, 4 cents a share above estimates. Revenue also beat forecasts, and an unchanged performance for comparable-store sales was better than the 0.2 percent decline that analysts had anticipated. Results were helped by strong sales of high-end jewelry.

Apple — The company is working to resolve a software glitch in its new MacOS High Sierra operating system, which allows anyone to get into a computer without using a password.

Wingstop — Guggenheim downgraded the restaurant chain to "neutral" from "buy," based on valuation after a 35 percent year-to-date gain and on concerns about an upcoming change in the way Wingstop recognizes revenue.

Domino's Pizza — Instinet upgraded the stock to "buy" from "neutral," following a 21 percent pullback in the stock from its most recent highs and possible further opportunities for international expansion.

Autodesk — The software maker announced a restructuring plan which will see layoffs of about 13 percent of its workforce. The company also said it lost an adjusted 12 cents per share for its latest quarter, 1 cent a share smaller than expected. Revenue topped forecasts.

Marvell Technology — Marvell reported adjusted quarterly profit of 34 cents per share, 1 cent a share above estimates. The chipmaker's revenue also came in above Street forecasts. Marvell also gave an upbeat current quarter forecast, as demand for its networking and connectivity chips increases.

Nuance Communications — Nuance earned an adjusted 20 cents per share for its latest quarter, 5 cents a share above estimates. Revenue beat forecasts, as well. The voice and language solutions provider saw particular strength in its medical cloud-related offerings.

AT&T — AT&T and Time Warner filed a response to the Justice Department's objection to their planned merger, saying the proposed deal was "pro-competitive" and "Pro-consumer." The companies said the markets in which they participate are highly competitive now and would remain so after the deal is completed.

Regal Entertainment — Regal issued a statement confirming reports that the movie theater operator is currently in talks with Britain's Cineworld Group about possibly being acquired for $23 per share. Regal said no agreement had been reached and there was no assurance a final deal would be struck.

Wal-Mart Stores — Wal-Mart was upgraded to "sector perform" from "underperform" at RBC Capital, which said the retail giant's various investments will pay off in the long term lead people to increasingly view it as a true competitor to Amazon.com.

Qualcomm — The chipmaker was downgraded to "hold" from "buy" at Stifel Nicolaus, which thinks any negotiation with potential acquirer Broadcom will be protracted and that the current risk to the share price is to the downside.