Shares of Elon Musk's SpaceX climbed more than 14% on Tuesday, lifting its valuation past Amazon.com and briefly above Microsoft to rank it among the top-five most ‌valuable companies within days of a blockbuster debut. Shares of the rockets-to-AI company were last up 14.3% at $220, jumping ‌more than 62% above the $135 IPO price and giving the company a market capitalization of around $2.85 trillion if gains hold. The stock gave the biggest ​boost to the Nasdaq Composite index.