While the unlocking makes the shares available to trade, it’s up to the holder whether they want to sell or keep their shares. SpaceX shares (SPCX) rose more than 6% on Thursday. SpaceX sold roughly 640 million shares at its IPO, equivalent to less than 5% of its total shares. The Nasdaq 100 weights stocks based on their market value and the number of shares available for trading. The index rebalances every three months and will rebalance in September, accounting for updated levels of publicly available SpaceX shares.