Are Index Fund Rules Being Rewritten to Benefit Big IPOs?

The Quiet Rule Changes That Could Affect Every Index Fund Investor

If you invest in index funds, you probably assume you're getting a transparent, rules-based slice of the market. But behind the scenes, the companies that write those rules — S&P Global, FTSE Russell, MSCI, and NASDAQ — are quietly rewriting them. And the timing is no coincidence: some of the largest, most richly valued private companies in history are preparing to list on public markets.

SpaceX, OpenAI, and Anthropic are all circling the stock market. SpaceX alone is reportedly targeting a valuation of around $2 trillion — despite posting a net loss of $4.93 billion on $18.67 billion in revenue in 2025. If these companies enter the major indexes, every passive investor holding a global tracker or US equity fund will be forced to own a piece of them. The question is whether those investors are walking into an opportunity or being set up to absorb the exit of early-stage backers.

This isn't a fringe concern. It cuts to the heart of how index investing actually works — and exposes a structural tension that most retail investors have never had to think about before.

How Index Inclusion Actually Works — And Why It Matters

Most people treat 'the market' as a natural, objective phenomenon. It isn't. The S&P 500, the FTSE 100, the NASDAQ 100 — these are curated lists, built and maintained by private commercial companies. When you buy a fund that tracks one of these indexes, a portion of your fees flows directly to the index provider. These are businesses, not public utilities.

That commercial reality creates an inherent tension:

• Stability: Index rules need to be consistent and predictable. Trillions of pounds and dollars are allocated based on these rules. Arbitrary changes erode trust.
• Relevance: Index providers compete with each other. An index that excludes the most talked-about companies risks becoming irrelevant — and losing fee income.

When a company meets an index's eligibility criteria, fund managers tracking that index are obligated to buy its shares. There's no discretion. The fund doesn't evaluate whether the company is fairly valued — it simply rebalances to match the list. This mechanical buying is precisely why index inclusion is such a high-stakes event for both companies and investors.

For mega IPOs with sky-high valuations and thin public floats, getting into the index fast means guaranteed, large-scale demand from passive investors — regardless of fundamentals.

The Four Rule Changes Passive Investors Should Understand

Across at least three major index providers, meaningful rule changes have been introduced or are in progress. Here's what has changed and why it matters:

1. Shorter Seasoning Periods

Most indexes historically required a company to trade publicly for a period before qualifying for inclusion — giving the market time to price the business without index-driven artificial demand. In March, NASDAQ announced that companies can now qualify for the NASDAQ 100 after just 15 trading days, down from the previous three months. FTSE Russell has introduced a similar fast-track rule for the Russell 1000 and Russell 3000: if a company is large enough to rank in the top 500 of the index, it can enter after just five trading days.

S&P Global is more conservative. Its 12-month seasoning period for the S&P 500 is reportedly being reduced to six months — meaning SpaceX, at a $2 trillion valuation, likely wouldn't enter until mid-2027 at the earliest.

2. Lower Free Float Requirements

Free float refers to the proportion of a company's shares that are actually available for public investors to trade. Microsoft's free float is essentially 100%. Nvidia's is around 95%. SpaceX, however, could list with as little as 2–5% of its shares publicly available if it raises $50–75 billion against a $2 trillion valuation.

Historically, NASDAQ required a minimum 10% free float for index inclusion. That threshold has now been reduced. FTSE Russell has also updated its global index rules so that a company qualifies if it's expected to exceed a 5% free float within 12 months of listing — even if it lists below that level. Once insider lockup periods expire and early shareholders can sell, the float rises. Under these revised rules, SpaceX could qualify relatively quickly.

3. Free Float Multipliers

This is a nuance that much of the online commentary has missed — and it actually provides meaningful protection for passive investors. Rather than treating a company as if its full market cap were available (as older NASDAQ rules did), indexes now apply a free float multiplier when calculating a company's index weight.

If SpaceX lists at $2 trillion but only 5% of the company is floating, NASDAQ would treat it more like a $100–300 billion company for weighting purposes. Analysts estimate SpaceX would represent approximately 0.47–0.7% of the NASDAQ 100 under this methodology. For every £1 you invest in a NASDAQ 100 tracker, less than one penny would go to SpaceX — compared to roughly 7p to Apple.

FTSE Russell is even stricter: no multiplier at all. Only the free float counts. Under this approach, SpaceX could represent less than 0.2% of the Russell indexes. This is not a pension-destroying event. It is a meaningful but manageable exposure.

4. The NASDAQ Conflict of Interest

NASDAQ occupies a unique dual role in this story. It operates both as a stock exchange — competing with the New York Stock Exchange to win listings — and as an index provider. A CNBC interview with early SpaceX investor Ron Baron revealed that the New York Stock Exchange approached him directly, asking how it could persuade SpaceX to list there instead of NASDAQ.

If NASDAQ can attract a $2 trillion listing in part by offering faster index inclusion as an incentive, the integrity of the index-making process is genuinely compromised. NASDAQ hasn't stated this directly, and intent is impossible to prove from the outside. But the incentive structure is plain: change the index rules, win the listing, capture the fees. The conflict is structural, not conspiratorial — which arguably makes it harder to address.

SpaceX's Valuation: What the Numbers Actually Say

Setting aside the index mechanics, it's worth pausing on SpaceX's financials, because they're central to whether this represents a risk for passive investors.

At a $2 trillion valuation against 2025 revenues of $18.67 billion and a net loss of $4.93 billion, the implied price-to-sales ratio is between 93 and 107 times — depending on the valuation methodology used. For context:

• The average S&P 500 company trades at around 3.6x price-to-sales
• Palantir, frequently cited as overvalued, trades at around 67x
• Meta and Alphabet — companies some analysts argue are in bubble territory — trade at 7–12x

SpaceX's SEC filing claims a total addressable market of $28.5 trillion, encompassing rocket launches, asteroid mining, Mars colonisation, satellite internet, AI, social media, and data centres. To put that figure in perspective: the entire global food market — everything consumed on Earth — is estimated at roughly $10 trillion annually. SpaceX is positioning itself as potentially three times larger than food.

None of this means the investment will fail. Betting against Elon Musk's ability to raise capital and generate long-term enterprise value has historically been a losing trade. But the valuation prices in a future that hasn't happened yet — and passive investors will be buying in at whatever price the market sets at the point of index inclusion.

This Has Happened Before — And Index Investing Survived

Rule changes around high-profile listings are not new. Glencore was fast-tracked into the FTSE 100 in 2011. Saudi Aramco required bespoke treatment from multiple index providers around its 2019 listing — one of the largest IPOs in history. And in 1999, the Dow Jones Industrial Average rotated out Chevron, Goodyear, and Sears in favour of Intel, Microsoft, Home Depot, and SBC Communications — right before the dot-com bubble burst.

Passive investors weathered all of these moments. The long-term case for index investing — low cost, broad diversification, reduced behavioural risk — was not broken by any of them. The concern today is legitimate, but it deserves proportionality. The risk is not that SpaceX will become 10% of your portfolio. The risk is a structural one: that commercial incentives are quietly compromising the neutrality of the index-making process.

As one widely-held view among value investors goes — and Warren Buffett has suggested as much — IPO stands for 'Is Probably Overpriced.' The index inclusion mechanics described above mean passive investors don't get to act on that scepticism. They buy regardless.

What Passive Investors Should Actually Do

The honest answer is: probably not much different from what you're already doing. But awareness matters.

• Check your index's free float methodology. Funds tracking FTSE Russell global indexes and the NASDAQ 100 are most directly affected by recent rule changes. Look up the factsheet for your specific fund and understand how it handles free float weighting.
• Don't overreact to the weighting. Even under the most aggressive inclusion scenario, SpaceX is likely to represent well under 1% of most broad index funds. That's not a portfolio-defining position.
• Understand the conflict of interest. Index providers are commercial businesses. The rules they set reflect competitive pressures, not just market integrity. That doesn't mean you should exit passive investing — but it does mean passive investors should stay informed rather than assuming complete neutrality.
• If you want direct exposure, make a conscious choice. There is a meaningful difference between consciously choosing to buy SpaceX shares because you believe in the business, and having a fraction of your index fund allocated there automatically because of a rule change. The former is a decision. The latter is a consequence.

Index funds remain one of the most effective vehicles for long-term wealth building available to retail investors. But 'passive' has never meant 'uninformed.' The rule changes happening right now are worth understanding — not as a reason to panic, but as a reason to pay attention.

This article is for informational purposes only and does not constitute financial advice. Always consult a qualified financial professional before making investment decisions.

Frequently Asked Questions

Will SpaceX automatically enter my index fund if it IPOs? Not immediately, and not necessarily in a significant way. Whether SpaceX enters your fund depends on which index it tracks. NASDAQ 100 and Russell index funds are most likely to include it earliest, given recent rule changes. S&P 500 funds have a longer seasoning requirement — potentially until mid-2027. Even where SpaceX does qualify, its weighting in most broad funds is expected to be well under 1% due to free float multiplier rules.

What is a free float multiplier and why does it matter for index funds? A free float multiplier adjusts a company's effective index weight based on how much of it is actually available for public trading. If SpaceX lists at $2 trillion but only 5% of shares are publicly available, the NASDAQ 100 would weight it closer to a $100–300 billion company rather than $2 trillion. This significantly limits passive investors' involuntary exposure at launch, and is a detail frequently missing from coverage of this topic.

Is it a conflict of interest for NASDAQ to be both an exchange and an index provider? It creates a clear incentive problem, even if no wrongdoing can be proven. If NASDAQ can win a prestigious listing like SpaceX partly by offering faster index inclusion — boosting its exchange revenues — the commercial motive to alter index rules is obvious. The CNBC interview with Ron Baron suggests the NYSE was actively competing for the listing, which puts the decisions NASDAQ makes as an index provider in a different light. Whether that constitutes a conflict of interest in a legal sense is a separate question.

Should I stop investing in index funds because of these rule changes? The data does not support that conclusion. Historical precedents — including Glencore's fast-tracked FTSE 100 entry in 2011 and Saudi Aramco's inclusion — show that index investing has remained robust through similar episodes. The structural concern about commercial incentives influencing index rules is legitimate and worth monitoring, but the practical impact on a diversified passive portfolio is likely to be modest. The more important action is understanding which specific indexes your funds track and reviewing how those providers handle free float and seasoning rules.