The index committee rule changes that preceded SpaceX’s record-breaking IPO have set a trap for the passive investment funds that have become the backbone of American retirement accounts. The mechanism is brutally simple: when a stock is forced into a major index faster than the market can absorb it, passive funds must buy at any price. That price might be inflated by the very euphoria the committees sought to capture.
SpaceX went public on June 12, raising $75 billion — nearly three times the previous record-holder, Saudi Aramco’s December 2019 IPO. It briefly touched a valuation of almost $3 trillion before its post-IPO gains were pared back.
That paring was the first sign of trouble. The correction that followed is exactly the scenario index committees were supposed to guard against. Instead, the new rules may accelerate it.
The implication for everyday investors is direct. Millions of Americans hold index funds in their 401(k)s and IRAs.
When a stock enters an index at an inflated price, those funds buy shares at the peak. If the stock corrects — as SpaceX’s post-IPO performance already suggests is happening — the losses are locked into the portfolios of people who never chose to own the stock at that price. They simply followed the index.
Anthropic and OpenAI are waiting in the wings. Both filed confidentially with the Securities and Exchange Commission — Anthropic on June 1, OpenAI on June 8. By June 18, secondary markets were pricing Anthropic at an estimated $965 billion and OpenAI at $909 billion.
Those valuations are built on hype, not earnings. The same index committees that rewrote the rules for SpaceX will face the same pressure to fast-track these companies into major benchmarks.
The same trap will spring again. The broader market is at risk. The Dow has risen 57% during the Trump bull market.
The S&P 500 has gained 70%. The Nasdaq Composite has surged 142%.
Those gains have been fueled by what the market calls “IPO euphoria,” and nobody has delivered euphoria quite like Elon Musk’s SpaceX. But the rally has also been fed by share buybacks that hit an all-time high in 2025. Companies have been borrowing cheap money to prop up their stock prices.
That strategy works only as long as the music keeps playing. The technical detail that matters is this: the index committees changed the rules before SpaceX’s debut. The presumption is that Nasdaq Global Indexes wanted to court the world’s largest IPO to list on its exchange.
The consequence is that newly implemented rules can very easily turn the tables. What was meant to attract a prize listing now threatens to destabilize the passive investment machinery that has underpinned the bull market.
Watch the secondary market pricing for Anthropic and OpenAI in the coming weeks. If their valuations start to slip before they even go public, the entire IPO euphoria narrative weakens. If the indexes fast-track them anyway, the passive buying mechanism forces funds to absorb shares at whatever price the market sets — even if that price is falling.
The committees created a system that amplifies both the highs and the lows. The lows are coming.
The champagne corks are still bouncing. But the index committees have quietly rewired the party’s sound system. When the music stops, the passive funds will be the first to hear the silence.
