Check out the companies making headlines midday Tuesday:
Bed Bath & Beyond — Shares of the merchandise retail store jumped 22 percent as three activist investors, Legion Partners Asset Management, Macellum Advisors and Ancora Advisors, are preparing to replace the company's board. A person familiar with the situation said plans are to oust long-term Chief Executive Steven Temares.
Nvidia — Nvidia climbed 1.8 percent after the chipmaker was initiated with an overweight rating at Piper Jaffray. Piper said the company is trading at attractive levels and is positioning itself for growth.
Viacom — Shares of Viacom rose more than 7.6 percent as the company reportedly restarted merger talks with CBS. A New York Post report said CBS independent directors are expected to talk to the company's board in the next few weeks, which could be followed by CBS approaching Viacom with an offer.
Criteo — The internet advertising company's stock fell more than 17 percent after downgrades from KeyBanc Capital Markets and SunTrust following reports that Google was considering changes to its Chrome and Google Marketing Platform.
World Wrestling Entertainment — Shares of World Wrestling Entertainment gained 1.2 percent after MKM Partners raised its price target on the stock to $110 from $95. The new outlook would translate into a 23 percent gain based on Tuesday's trading level. MKM said the professional wrestling media company "looks very attractive" with the incremental international TV deals and the re-launch of its network.
McDonald's — The fast-food giant's stock rose 1 percent after McDonald's acquired Dynamic Yield, a company with the technology needed for McDonald's to create personalized drive-thru menus. McDonald's paid $300 million for Dynamic Yield, its largest deal in two decades.
Tesla — Shares of Tesla rose 2.82 percent after a federal judge in San Francisco dismissed a securities fraud lawsuit brought by Tesla shareholders against the electric vehicle company. This is the second time a judge has dismissed a securities lawsuit against Tesla.
IHS Markit — The global information company dipped more than 1.5 percent after reporting mixed quarterly results. The company posted earnings per share of 60 cents, topping a Refinitiv estimate by 3 cents. However, IHS' revenue of $1.046 billion missed expectations.
Carnival — Shares of the cruise operator dropped more than 8 percent after the company slashed its full-year earnings outlook. Carnival expects earnings per share to range between $4.35 and $4.55, down from a prior guidance of $4.50 to $4.80.
—CNBC's Yun Li, Nadine El-Bawab and Jessica Bursztynsky contributed to this report.