SpaceX shares are extending their steep upward run. Following the largest IPO in history, the stock posted another sharp gain on its second trading day yesterday (Monday) — propelling Elon Musk’s rocket and satellite company into the ranks of the world’s most valuable companies within just a few days. Two trading days, one steep climb On Monday, its second trading day, SpaceX stock rose roughly +19.6% on the Nasdaq, closing at $192.50 . That continued the strong momentum of its debut: on day