SpaceX will make a historic stock-market debut in the coming weeks, but some retail traders say there's one thing stopping them from buying on day one. Everyday investors speaking with Business Insider said that the colossal valuation is hard for them to get behind. Elon Musk's rocket company will likely be the largest IPO in history, with an expected valuation of $1.75 trillion to $2 trillion and $75 billion raised when it offers shares to investors. For some retail traders watching from the