Catenaa, Tuesday, September 08, 2026- A wave of new buying in SpaceX stock may soon arrive when the Nasdaq 100 Index goes through its quarterly rebalancing later this month.
The key is the combination of a little-discussed rule in the tech-heavy benchmark’s construction and a staggered series of lockup periods for shareholders of Elon Musk’s satellite and space exploration venture that has limited the number of shares available to trade.
Nasdaq determines a company’s weighting in the index based on a calculation of its market value that factors in either its total outstanding shares or three times its free-floating shares, whichever is lower.
This means a stock with a low free float, which excludes shares held by insiders or those subject to lockups, will not have its full market value used to calculate its weighting.
For SpaceX, which has a relatively small free float because of lockup restrictions, that leaves it with a weighting of 1.25% in the Nasdaq 100, which is 19th biggest, despite sporting the sixth largest market capitalization in the index at more than $2 trillion.
But that weighting is expected to rise after the index’s next rebalancing, which is set to be announced on Friday after the bell and take effect on September 21.
That’s due in part to the fact that more than one billion shares have now been released from lock-up restrictions, boosting its free float to nearly 30% of SpaceX’s outstanding shares from less than 10% immediately after the IPO.
SpaceX’s weighting could hit 2.25% after the rebalance, forcing $15.5 billion of net passive buying from index funds and ETFs, according to estimates by JPMorgan Securities strategists led by Min Moon.
Roughly $1.7 trillion in assets track the Nasdaq 100 as of the end of the second quarter, according to Nasdaq, including the Invesco QQQ Trust Series 1 exchange-traded fund, better known by its ticker symbol QQQ.
As more SpaceX shares are unlocked over the next year, the company’s free float will continue to rise, meaning its Nasdaq 100 weighting could potentially increase even more.
After a buzzy record IPO in June that set off weeks of volatile trading, SpaceX shares have gone quiet.
The stock has traded sideways over the last four weeks, holding in a range between $133 and $150, right around its IPO price of $135. With few fundamental catalysts on the horizon, the index rebalancing could provide the juice the shares need to break out.
Nasdaq isn’t the only index provider to calculate its weightings like this. S&P Dow Jones Indices, which manages the S&P 500, also uses a float-adjusted market capitalization to determine weightings in some of its gauges.
When Berkshire Hathaway slashed its stake in Apple two years ago, it boosted the stock’s float value, which analysts at Piper Sandler estimated at the time would spur $40 billion in buying by passive funds.
While SpaceX was also added to the Russell 1000 Index in June, S&P 500 rules require a stock to have at least 12 months of trading history before joining. So it won’t be eligible until at least mid-2027.
SpaceX’s initial lockup expiration in August, which coincided with its first earnings release, stoked concerns about a major selloff on the theory that the sudden increase in the supply of shares would overwhelm demand.
But that didn’t materialize, even after a second expiration a week later, as insiders largely held onto their stakes, giving investors optimism and propping up the stock price.
More than one billion additional shares will be unlocked by the end of October, with another 1.3 billion becoming eligible to trade after the company reports its third-quarter earnings in mid-November.
