June 10, 2026 | U.S. Growth and Core Equity
Portfolio Specialist
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SpaceX’s initial public offering (IPO) is generating more than investor excitement; it’s also helping to reshape how major indexes accommodate large, newly public companies. Yet despite an expected valuation exceeding $1.7 trillion, its initial weight in major equity indexes may be far smaller than the headlines suggest.
For our Large Cap Growth and All Cap Growth strategies, the most relevant index developments come from FTSE Russell, whose indexes serve as our benchmarks. Drawing on publicly available information from FTSE Russell and SpaceX, below we summarize the key rule changes, potential index impacts, and considerations we believe are most relevant for investors.
FTSE Russell’s recent rule changes did not occur in isolation. Across the industry, index providers have been evaluating how their methodologies should accommodate a new generation of expected mega-cap IPOs, including SpaceX, OpenAI, and Anthropic. Against that backdrop, FTSE Russell updated its framework to accelerate the timeline for adding some newly public companies to its indexes.
Under the revised approach, companies whose float-adjusted (investable) market capitalization exceeds the Russell Top 500 eligibility threshold (currently estimated at roughly $17.5 billion) can be added to applicable indexes shortly after going public.
For most qualifying IPOs, index inclusion can occur as soon as five trading days after listing. The change is intended to allow indices to more quickly reflect the evolving opportunity set available to investors, particularly when large companies enter the public markets.
There is, however, an important exception. When an IPO occurs close to one of FTSE Russell’s semi-annual reconstitution quiet periods, the company may be added on the reconstitution effective date rather than through the standard five-day process. Because SpaceX’s anticipated listing date falls near the June reconstitution, FTSE Russell has indicated that the company is expected to be added through the reconstitution process rather than under the standard fast-entry timetable.
While FTSE Russell accelerated the timeline for adding large IPOs to its indexes, it chose not to modify its existing requirements related to public float and voting rights. To qualify for index inclusion, companies are generally expected to maintain at least a 5% public float and 5% voting rights threshold.
That decision stands in contrast to some other index providers (such as Nasdaq) that have become more accommodating of companies entering the public markets with relatively limited public ownership. FTSE Russell ultimately determined that there was not sufficient support among market participants to broadly relax its float and voting rights standards.
Russell preserved its longstanding eligibility standards while creating a pathway for large companies with initially limited floats to enter the indices.
However, the firm did introduce an important degree of flexibility with a grace period provision. Companies that fall below the 5% thresholds at the time of their IPO may still qualify for accelerated index inclusion if scheduled lock-up expirations are expected to increase public float and voting rights above the minimum levels within 12 months. As additional shares become eligible for trading, those changes would be reflected through FTSE Russell’s normal review process.
The distinction is important because it preserves Russell’s longstanding eligibility standards while creating a pathway for large newly public companies with initially limited floats to enter the indices, provided their ownership structure is expected to broaden over time.
Based on its most recent S-1 filing, SpaceX is pricing 555.6 million shares at $135 per share, raising approximately $75 billion at a $1.77 trillion valuation, the largest IPO in history. Yet the company is expected to float around 4% to 5% of total shares outstanding.
Using the assumptions outlined in its May analysis, FTSE Russell estimates SpaceX would enter the market with approximately $70 billion in float-adjusted market capitalization, despite a total valuation measured in the trillions. That figure is well above the threshold required for accelerated index inclusion, suggesting SpaceX satisfies the size requirement for fast entry.
SpaceX would enter the market with approximately $70 billion in float-adjusted market capitalization, despite a total valuation measured in the trillions.
On the float and voting rights requirements, FTSE Russell expects the 180- to 366-day lock-up schedule outlined in SpaceX’s S-1 filing to increase public float and voting rights above the 5% minimum threshold within 12 months of index inclusion, allowing the company to qualify under the grace-period provisions.
As a result, SpaceX appears positioned to meet Russell’s eligibility requirements despite its relatively limited initial float. More broadly, the revised framework is intended to accommodate large IPOs that enter the public markets with concentrated ownership structures but a clear path toward broader public ownership over time.
Meeting the eligibility requirements, however, is only part of the story. The more important question for many investors is how much SpaceX will actually matter within major indexes once it is added.
One of the key takeaways from FTSE Russell’s analysis is the difference between SpaceX’s headline valuation and its expected index weight. Although the company is expected to debut with a valuation exceeding $1.7 trillion, index weights are based on float-adjusted market capitalization, meaning the company’s initial representation in the Russell indexes is likely to be far smaller than the valuation alone would suggest.
The projected weights highlight the gap between SpaceX’s headline valuation and its actual index footprint. However, those weights are unlikely to remain static. As lock-up restrictions expire and additional shares enter the public float, SpaceX’s float-adjusted market capitalization could increase, potentially resulting in higher index weights over time. As a result, index-related buying pressure may occur in stages rather than as a single event at IPO.
SpaceX could initially be assigned a meaningful value tilt despite being widely viewed by investors as a growth company.
Another interesting aspect of FTSE Russell’s analysis is SpaceX’s expected classification within the Russell framework. FTSE Russell currently anticipates classifying the company within the telecommunications sector, largely reflecting the significant contribution of Starlink to the company's revenue base. For newly public companies entering through the fast-entry process, style classifications are initially derived from the average style characteristics of the assigned Industry Classification Benchmark sub-sector rather than company-specific fundamentals, which are not yet available at the time of inclusion. Because the telecommunications sub-sector currently exhibits an average style profile of approximately 18% growth and 82% value, SpaceX could initially be assigned a meaningful value tilt despite being widely viewed by investors as a growth company.
Importantly, this initial classification should be viewed as provisional rather than a statement about SpaceX’s underlying fundamentals. FTSE Russell has indicated that the company’s style assignment will be revisited once sufficient company-level data becomes available. The firm has also retained discretion to adjust the classification if the default sector-based approach is deemed unrepresentative of the company’s business characteristics.
The projected index weights suggest that the initial mechanical buying pressure associated with SpaceX’s inclusion may be more modest than the company’s headline valuation would imply. At the same time, future lock-up expirations and increases in public float could create additional index-related rebalancing activity over the following quarters.
For active managers, however, the more important question is not when a company enters an index, but whether its long-term fundamentals justify investment. Consistent with our bottom-up research approach, we are evaluating upcoming IPOs—including SpaceX, OpenAI, and Anthropic—through the lens of competitive advantages, growth durability, valuation, and long-term earnings potential.
While index mechanics can influence short-term trading dynamics, long-term returns are ultimately driven by business fundamentals. Our focus remains on identifying companies whose durable growth potential is not yet fully reflected in market expectations.
Aaron Socker is a portfolio specialist on William Blair’s U.S. growth and core equity team.
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