Check out the companies making headlines in midday trading.

GoDaddy — The web hosting company saw its shares jump 8.4% following a Wall Street Journal report that activist investor Starboard Value has taken a 6.5% stake in it, worth roughly $800 million.

Delta Air Lines — Shares of airlines declined, but rallied off their lows Monday following thousands of canceled flights over the holiday weekend amid staffing shortages. Delta lost 0.8%, United dipped 0.7% and American Airlines shares also traded 0.5% lower. More than 2,000 flights were canceled from Christmas Eve through Sunday evening. Carriers cited the spread of the omicron Covid variant among crews as behind the cancellations, with bad weather also affecting flights.

Norwegian Cruise Line, Royal Caribbean — Cruise line shares also retreated after reported Covid outbreaks on ships. Royal Caribbean slid 1.4%. Carnival fell 1.2%, and Norwegian Cruise Line dipped 2.6%.

Las Vegas Sands, MGM Resorts — Shares of casino operators sold off in unison as the omicron variant dents demand for travel and leisure. Las Vegas Sands fell 1.9%. Wynn Resorts retreated 1,5%, and MGM Resorts dipped 1.2%.

APA Corp, Devon Energy — Energy names rose as oil prices moved higher. APA Corp added 7.3%, Devon Energy gained 6.1%, and Diamondback Energy rose 4.9%.

Moderna — Moderna shares dipped 1.2% after the Financial Times reported the drugmaker is fighting a shareholder proposal that the company open up its vaccine technology to poorer countries. The proposal calls on Moderna to explain why its prices are so high in light of the amount of government financial support it has received.

Didi Global — Chinese ride-hailing company Didi’s shares fell 5.4% after the Financial Times reported Didi is blocking employees from selling company shares for an indefinite period. That follows a move by the company earlier this month to delist the stock in the United States.

Ralph Lauren, American Eagle — Retail stocks rose on Monday after early holiday shopping sales numbers showed strong consumer spending in recent weeks. Shares of Ralph Lauren rose 4.3%, while American Eagle’s stock jumped 3.5%

— CNBC’s Jesse Pound, Tanaya Macheel, Pippa Stevens and Yun Li contributed reporting