SpaceX is preparing to go public in what could become one of the largest IPOs in history, targeting a valuation between $1.75 trillion and $2 trillion. But the real story isn’t the size of the offering. It’s the mechanics of what happens after.

With a public float estimated at just 3% to 4% of total shares and passive index funds projected to scoop up roughly 30% of that float within 15 trading days, SpaceX’s debut could trigger a feedback loop where automated buying pushes prices higher, which triggers more automated buying.

The setup: a very thin float meets very large buyers

SpaceX is targeting a Nasdaq listing around June 12, 2026, under the ticker SPCX, with pricing expected the day before at $135 per share. The company filed confidentially with the SEC on April 1, 2026, and released its public S-1 prospectus on May 20.

The IPO aims to raise between $50 billion and $75 billion. The public float will represent only 3% to 4% of total outstanding shares. Founder shares carry a 366-day lock-up period, and major investors face similar restrictions.

The index inclusion fast track

Nasdaq has updated its rules in 2026 to allow fast-track inclusion of mega-IPOs into its benchmarks. Under these new provisions, SpaceX could be added to the Nasdaq 100 within as few as 5 to 15 trading days after its debut.

Current forecasts suggest passive investors could accumulate approximately 30% of the available free float in that narrow window. Index funds buy shares because SpaceX is in the index. Their buying pushes the price up. A higher price increases SpaceX’s market cap weighting in the index. A higher weighting means funds need to buy even more shares to stay properly allocated.

Short-squeeze dynamics and the float-adjusted safety valve

Most broad-market indexes use float-adjusted weighting, which means they calculate a stock’s index weight based on its tradable shares rather than its total market capitalization. For SpaceX, this means its effective presence in funds tracking the S&P 500 and other total market indexes would be capped well below 0.5%.

The Nasdaq 100 itself doesn’t have the same cushion. A fast inclusion with a $1.75 trillion-plus valuation would make SpaceX one of the largest constituents immediately.

What this means for investors

When 30% of available shares are being absorbed by funds that have no choice but to buy, price discovery becomes less about what SpaceX is worth and more about supply-demand mechanics.

The 366-day lock-up on founder and insider shares means this scarcity dynamic has a defined expiration date. When those shares eventually unlock, the float expands dramatically.

Anyone holding a Nasdaq 100-tracking fund should understand they’ll be getting meaningful SpaceX exposure very quickly after the IPO. Float-adjusted weighting keeps the position size manageable in broad portfolios.