SpaceX is days away from what would be the largest initial public offering in history, and, predictably for an Elon Musk company, it is doing things differently. Rather than following the conventional playbook, where companies announce a price range, spend weeks on investor roadshows, and set a final price based on demand, SpaceX has opted for the highly unusual approach of setting a fixed price of $135 per share ahead of presentations to investors and formal bookbuilding.