SpaceX、OpenAI 与 Anthropic IPO：2.9 万亿美元市值的市场压力测试
SpaceX, OpenAI & Anthropic IPOs : A $3 Trillion Stress Test
Tomer Tunguz 分析 SpaceX（目标 1.5 万亿美元）、OpenAI（1 万亿美元）与 Anthropic（3800 亿美元）合计 2.9 万亿美元市值 IPO 对公开市场的冲击。
作者用流通盘比例和 S&P 500 纳入规则推算三家 IPO 的资金规模与指数被动买卖压力，提供了一个可验证的市场影响视角。
In short : SpaceX, OpenAI & Anthropic IPOs totaling $2.9t in market cap would require $432-576b at standard float percentages, nearly matching the entire 10-year US IPO total. Tiny floats (3-8%) will delay S&P 500 inclusion, but when these companies qualify, index funds must sell existing mega-caps to buy new entrants.
We’re about to witness three of the largest IPOs in history. SpaceX is targeting $1.5t.1 OpenAI aims for $1t.2 Anthropic is valued at $380b.3 Combined, $2.9t in market cap.
The scale is unprecedented. But the real problem isn’t the market cap. It’s the float.
Typical IPOs offer 15-25% of their shares to public markets. This creates enough liquidity for price discovery while allowing founders & early investors to maintain control. Facebook floated 15%. Google floated 19%. Alibaba floated 15%.
At a 15% float, here’s what these three IPOs would require :
| Company | Market Cap | Float at 15% | Float at 20% |
|---|---|---|---|
| SpaceX | $1.5t | $225b | $300b |
| OpenAI | $1.0t | $150b | $200b |
| Anthropic | $380b | $57b | $76b |
| TOTAL | $2.9t | $432b | $576b |
At standard float percentages, these three companies would need to raise $432-576b from public markets in a single quarter. From 2016 to 2025, the entire US IPO market raised $469b.4
It’s like throwing a boulder into a pond. Standard floats are impossible, so these companies will debut with tiny ones, likely 3-8%.
But that creates a different problem. The S&P 500 requires 50% public float for inclusion.5 At 3-8%, none qualify initially. When they do, the disruption begins.
| Rank | Company | Market Cap |
|---|---|---|
| 1 | Apple | $3.4t |
| 2 | Microsoft | $3.1t |
| 3 | NVIDIA | $2.8t |
| 4 | Alphabet | $2.3t |
| 5 | Amazon | $2.2t |
| 6 | Meta | $1.6t |
| 7 | Berkshire Hathaway | $1.1t |
Source : Yahoo Finance6
SpaceX at $1.6-2t would challenge Meta for spot #6, potentially slotting in behind Amazon. When they qualify, passive funds managing $20t must buy. Index funds can’t raise cash. They sell existing holdings.
The mechanics become self-reinforcing. Index funds sell existing mega-caps to buy new entrants. Lower mega-cap prices trigger momentum strategies to sell further. Additional selling creates more pressure on the very stocks index funds track.
These companies have challenged every assumption within their core markets. Now their IPOs will challenge every assumption about public financial markets.
References
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Bloomberg. “SpaceX Said to Pursue 2026 IPO Raising Far Above $30 Billion.” December 2025. https://www.bloomberg.com/news/articles/2025-12-09/spacex-said-to-pursue-2026-ipo-raising-far-above-30-billion ↩︎
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Bloomberg. “OpenAI May Target $1 Trillion Valuation in IPO.” October 2025. https://www.bloomberg.com/news/articles/2025-10-29/openai-could-target-1-trillion-value-in-ipo-reuters-says ↩︎
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CNBC. “Anthropic closes $30 billion funding round at $380 billion valuation.” February 2026. https://www.cnbc.com/2026/02/12/anthropic-closes-30-billion-funding-round-at-380-billion-valuation.html ↩︎
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Renaissance Capital. IPO proceeds data 2016-2025. https://www.renaissancecapital.com/IPO-Center/Stats ↩︎
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S&P Dow Jones Indices. “S&P U.S. Indices Methodology.” October 2025. https://spindices.com/documents/methodologies/methodology-sp-us-indices.pdf ↩︎
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Yahoo Finance. Market capitalization & float data accessed February 23, 2026. https://finance.yahoo.com/ ↩︎
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来源：Tomer Tunguz 博客（VC 分析） · tomtunguz.com