How Will it Affect the S&P 500?
By Jacob Mullen, Quantitative Derivatives Trader
The time is finally upon us, SpaceX is gearing up for a June 2026 Nasdaq IPO under the ticker SPCX, targeting a valuation between $1.5 trillion and $2 trillion while raising more than $75 billion. If successful, it would become the largest IPO in history and could reshape major stock indexes in the process.
“If successful, SPCX would become the largest IPO in history and could reshape major stock indexes in the process.”
While the offering is unusual for its size, it’s also making waves with the way major index providers are changing their rules to accommodate it. Proposed (and in some cases adopted already) methodology changes at S&P Dow Jones, Nasdaq, and FTSE Russell could allow SpaceX to enter indexes much earlier than traditionally permitted. That inclusion would force passive index funds to buy billions of dollars of SpaceX stock, funded by selling existing holdings across their portfolios.
Why the Rules Are Changing
Historically, newly public companies must check several boxes before joining major indexes. For example, the S&P 500 typically required: at least 12 months of public trading, four consecutive quarters of positive GAAP earnings, and minimum public float requirements (how many shares are available for trading). SpaceX currently falls short on several of those measures.
However, index providers are eager to fast-track SpaceX regardless. Supporters would say this is necessary to evolve with modern capital markets and they need to capture the largest and most influential companies as quickly as possible.
How Passive Funds Are Affected
When a company joins an index, the billions of dollars in passive funds tracking the indexes are obliged to purchase the new company’s shares. The steps are as follows when the rebalance window comes around:
- The index provider assigns a target weight to the new constituent.
- Index funds sell small portions of existing holdings.
- The proceeds are used to purchase the new stock.
This dynamic is likely to create substantial demand for SpaceX, as only an estimated 3–5% of shares are expected to be publicly tradable. That relatively small float could magnify the impact of mandatory buying.
Potential Scale of the Buying Pressure
Passive funds are conservatively estimated to be required to buy between $15 billion and $30 billion of SpaceX shares. Under aggressive scenarios (if special float-adjustment rules are applied, for example), demand may exceed $100 billion and potentially approach $200 billion across the broader passive investment ecosystem.
The S&P 500 has, as of 6/8/26, decided to not add SpaceX to their index immediately. However, the Nasdaq-100 and Russell 1000 are indicating they will be adding SpaceX roughly 15 trading days after IPO. The largest buyers would likely be funds tracking:
- The Nasdaq-100, including QQQ.
- The Russell 1000 and related benchmark products.
Passive fund managers would sell proportional amounts of existing holdings, including large positions in companies such as Apple, Microsoft, Nvidia, Amazon, and Alphabet.phabet.
Lessons from Tesla’s S&P 500 Inclusion
A common parallel market observers draw is to Tesla’s entry into the S&P 500 in late 2020. It’s important to note, however, that Tesla did meet the requirements to join the index at the time. It had been listed for many years and had finally achieved profitability.
Tesla rallied sharply between the inclusion announcement and the actual rebalance as traders anticipated forced buying by index funds. After the stock entered the index, momentum faded and shares traded sideways to lower as the one-time demand surge dissipated.
SpaceX could experience a similar pattern, but with two important differences: a much lower public float and a significantly faster path into the Nasdaq-100. Those factors could compress the timeline and intensify price volatility around inclusion dates.
Criticism vs Support
Critics of SpaceX’s accelerated timeline raise questions about whether index funds may be compelled to buy a newly public company at elevated valuations. It’s created unprecedented, guaranteed demand that benefits issuers, bankers, and early investors while transferring rebalancing costs to index holders.
As mentioned prior, some may argue that indexes must evolve to reflect modern capital markets and ensure that major benchmarks capture the largest and most influential companies as quickly as possible.
Bottom Line
SpaceX’s IPO, along with many other mega-IPOs on the horizon, are more than your average corporate listing. They could become a major market event driven by index mechanics. Rule changes at Nasdaq, S&P, and FTSE Russell may accelerate the company’s inclusion into key benchmarks, triggering tens of billions of dollars in forced buying from passive funds. Whether investors view that as an opportunity or a risk, the resulting flows are likely to be among the most closely watched market events of 2026.
