SpaceX Shareholder Equity Lock-up Period Know the details before placing your bets. Based on the currently disclosed SpaceX IPO lock-up arrangements, the company is using a “staggered lock-up” structure, which has been extremely rare in the U.S. stock market in recent years, instead of the traditional IPO model of a one-time 180-day lock-up period. According to the prospectus information compiled by the market, the IPO float will only account for about 5% of the total shares. Starting in August, existing shareholder holdings will be gradually released, with most of the lock-up ending by December 2026. However, shares related to founder Elon Musk will remain locked until June 2027.