Check out the companies making the biggest moves premarket: Regeneron Pharmaceuticals — The drugmaker fell more than 11% after its treatment for a skin cancer missed goals in a late-stage trial. Macy's — The department store shares jumped nearly 4% in premarket after a regulatory filing revealed Berkshire Hathaway initiated a small position in the company, valued at roughly $55 million at the end of the first quarter. The stake is very small for the conglomerate, so many speculated it was bought by investment lieutenant Ted Weschler, who manages 6% of the equity portfolio. Dominion Energy — Shares popped more than 12% after NextEra Energy announced a deal to acquire the company in an all-stock transaction. NextEra said the combination of the two companies will create the world's largest regulated electric utility business. Bio Rad Laboratories — The stock jumped 13% following a Wall Street Journal report that activist Elliott Investment Management has built a sizable stake in the company. However, the exact size of the stake nor Elliott's vision for the company were not detailed in the report. Arm Holdings — Shares were down 1% after a Bloomberg report Friday that a probe by the U.S. Federal Trade Commission is investigating if the company is illegally monopolizing parts of the chip market. Delta Air Lines — Shares were up more than 1% after a regulatory filing showed Berkshire Hathaway took a sizable stake in the airline, at a total of $2.6 billion . It comes six years after Warren Buffett moved Berkshire's entire equity portfolio out of airlines. UnitedHealth — The insurer was off more than 3.5% after it was revealed in the same regulatory filing that Berkshire Hathaway had sold shares of some of the company in the first quarter. Salesforce — Shares tumbled 1% after Bank of America reinstated coverage of the company at underperform. The bank wrote it expects a structural reset for Salesforce due to artificial intelligence, hitting the company's growth. ServiceNow — The software company jumped more than 4% following Bank of America reinitiating coverage of the stock with a buy rating. ServiceNow will likely benefit from AI, not be replaced by it, the bank wrote. Coinbase , Robinhood — Shares of the trading platforms tumbled after Bitcoin prices fell more than 5% over the weekend, dipping below 77,000 for the first time since early May. Coinbase fell more than 2.5%, while Robinhood was off almost 2%. Ford Motor — The stock jumped more than 6.5% after Ford Energy and EDF power solutions North America announced a five-year agreement where they'll produce up to four gigawatt hours of direct current Block Battery energy storage systems annually. Ford Energy is a subsidiary of the company, and deliveries as part of the agreement are expected to begin in 2028. — CNBC's Yun Li contributed reporting
