Stocks making the biggest moves premarket: Regeneron, Dominion Energy, Macy's & more

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. …