Check out the companies making headlines in midday trading. General Mills — Shares tumbled 7% after the Lucky Charms and Progresso parent lowered its 2026 outlook. General Mills said organic net sales would slide between 1.5% and 2%, while operating profit and adjusted earnings per share would tumble between 16% and 20%. Southwest Airlines — The airline’s stock jumped more than 6% after receiving an upgrade from UBS to buy. The analyst called Southwest’s new initiatives, which could attract travelers such as extra leg room and assigned seats. Warner Bros. Discovery , Paramount Skydance — Shares of the two media and entertainment companies rose after Netflix granted Warner Bros. Discovery a seven-day waiver to hold deal talks with Paramount Skydance. Warner Bros. Discovery gained nearly 3%, while Paramount jumped more than 6%. Tripadvisor — Shares of the travel booking website rose more than 7% after the company said its board and management have had conversations with activist investor Starboard Value, which holds a 9% stake in Tripadvisor. The hedge fund has asked the company to consider a sale of its business. Genuine Parts — Shares fell more than 12% after Genuine Parts said it planned to split its automotive parts group and its industrial parts group into two publicly traded companies. That decision followed a strategic review it underwent as part of its deal with activist Elliott Investment. The company also reported fourth-quarter earnings and revenue that fell short of expectations. Masimo , Danaher — Shares of health tech giant Masimo rallied more than 34% after The Wall Street Journal and Financial Times reported, citing sources, that the company was nearing a deal with Danaher to be acquired for $180 per share, or $10 billion, in cash. Shares of Danaher slid about 3%. Norwegian Cruise Line Holdings — The cruise operator moved more than 10% higher after Elliott Investment Management said it built a more than 10% stake in the company. The activist investor plans to press for changes to turn around Norwegian’s performance, according to a Wall Street Journal report . The company’s stock has lagged behind its competitors, Royal Caribbean and Carnival. ZIM Integrated Shipping Services — Shares surged 30% after German-based international container shipping and logistics company Hapag-Lloyd Aktiengesellschaft said it will buy Israeli competitor ZIM Integrated Shipping Services in a $4.2 billion transaction, in cash and external financing. Vulcan Materials — The U.S. producer of construction aggregates slid 5% after posting disappointing results. Vulcan reported adjusted EBITDA of $518 million in the fourth quarter, below the FactSet consensus estimate of $603.1 million. Revenue of $1.91 billion came in below the anticipated $1.96 billion. Labcorp — The global life sciences company fell more than 3% despite reporting fourth-quarter results that exceeded expectations. Labcorp earned $4.07 per share, excluding items, on revenue of $3.52 billion. Analysts polled by FactSet expected earnings of $3.94 per share on revenue of $3.56 billion. Labcorp shares have gained nearly 9% so far this year. Although the company’s forecast also topped the mid-point of estimates, there were some concerns about the pace of organic revenue growth. Leidos — Shares dropped nearly 3% after the tech company in defense and intelligence markets reported fourth-quarter revenue of $4.21 billion, weaker than the FactSet consensus estimate of $4.30 billion. On the other hand, adjusted earnings of $2.76 per share beat the expected $2.61 earnings per share. — CNBC’s Sarah Min, Alex Harring, Michelle Fox, Davis Giangiulio and Fred Imbert contributed reporting