Check out the companies making headlines in midday trading. Walmart — Shares of the big-box retailer dropped 1% after Walmart fell slightly short of first-quarter sales expectations and management warned that consumers could see higher prices caused by tariffs. Walmart reported revenue of $165.61 billion, while the consensus forecast was $165.84 billion, per LSEG. The retailer earned 61 cents per share, after adjustments, beating an LSEG estimate of 58 per share. Dick's Sporting Goods — The sporting goods retailer tumbled 14% on the announcement that it would buy rival Foot Locker for $2.4 billion , in a deal expected to close in the second half of this year. Shares of Foot Locker rallied 85% on the news. UnitedHealth — The health insurer plunged 15%, hitting an intraday low not seen in more than five years. The Wall Street Journal, citing people familiar with the matter, reported on Wednesday that the company is under Justice Department investigation for potential Medicare fraud. Fiserv — The financial technology stock fell 13% after management revealed its Clover business' second-quarter growth would be similar to the pace in the first quarter. The comments were made during JPMorgan's technology conference. Cisco — Shares popped nearly 6% following a better-than-expected earnings report for the network technology company's fiscal third quarter. Cisco earned 96 cents per share, excluding items, on revenue of $14.15 billion, while analysts polled by LSEG penciled in 92 cents per share and $14.08 billion in revenue, respectively. Cisco also gave strong guidance and announced finance chief Scott Herren would retire in July. Coinbase — Shares fell more than 4% after the digital currency platform said hackers bribed staff to steal customer data for use in social engineering attacks. The hackers are now demanding $20 million in ransom. Alibaba — Shares of the Chinese e-commerce giant tumbled 7% after the firm missed fiscal fourth-quarter expectations . Alibaba's net income rose 279% from a year ago, off a low base. Alibaba has been grappling with macroeconomic volatility that has dented consumer sentiment in China. Boot Barn — The Western retailer surged almost 17%, despite missing fiscal fourth-quarter estimates. The company said current-quarter same-store sales should rise more than predicted. Boot Barn plans to buy back as much as $200 million of its shares. CoreWeave — Shares of the artificial intelligence infrastructure company climbed 5% following its first earnings report as a public company. CoreWeave recorded $981.6 million in revenue, exceeding the $853 million figure anticipated by analysts surveyed by LSEG. DXC Technology — Shares of the IT services company declined almost 5% after the company issued weak guidance for the fiscal first quarter. DXC Technology expects adjusted earnings of 55 cents to 65 cents per share, while analysts polled by FactSet were expecting 79 cents per share. The company also provided a disappointing outlook for the full year. JetBlue — The airline's stock slid about 4% on the back of Raymond James' downgrade to market perform from outperform. Raymond James said JetBlue now has a more balanced risk-to-reward ratio. Aloca — The metal producer slipped 3% on the heels of UBS' downgrade to neutral from buy. UBS said the company's valuation isn't attractive. Webtoon Entertainment — Shares of the storytelling technology platform jumped nearly 12% following Citi's initiation at a buy rating. Citi said Webtoon, which beat analyst expectations when reporting first-quarter earnings earlier this week, is undervalued. — CNBC's Sean Conlon, Pia Singh, Yun Li and Lisa Kailai Han contributed reporting