SpaceX shares rose more than 4% on Thursday to close at $153.99, extending their gain from August lows to 42%, as investors focused on a potential wave of passive buying from the Nasdaq-100’s upcoming quarterly rebalance. JPMorgan Securities strategist Min Moon and his team estimate that SpaceX’s index weight could increase from 1.25% to 1.51%, requiring index funds and ETFs tracking roughly $1.7 trillion in assets to buy about $12.4 billion of the stock. The increase reflects Nasdaq’s methodology, which uses the lower of total shares outstanding or three times free-float shares when calculating constituent weights. More than 1 billion shares have been unlocked, lifting SpaceX’s free-float ratio from below 10% shortly after its June IPO to nearly 30%. Nasdaq is expected to announce the changes after Friday’s U.S. market close, with the new weights taking effect on September 21. Investors will also be watching additional unlocks of more than 1 billion shares by the end of October and roughly 1.3 billion shares after third-quarter results in mid-November. Market participants say the stock’s direction will depend on the balance between passive demand and selling from newly eligible holders.