Venture capital has unwritten rules. One of the most fundamental: don’t fund direct competitors. It creates conflicts of interest, poisons relationships, and signals that you don’t actually believe in either company enough to pick a winner.
That rule is breaking down in AI.
When Anthropic announced its $30 billion Series G earlier this month, at least a dozen firms that had already invested in OpenAI were on the cap table. Founders Fund. ICONIQ. Insight Partners. Sequoia Capital. D1 Capital Partners. Fidelity. TPG. These aren’t minor players making small bets. These are some of the most prominent names in venture capital, openly hedging.
Sam Altman Tried to Stop This
In 2024, Sam Altman reportedly gave OpenAI’s investors a list of rivals he didn’t want them to back. The list included Anthropic, xAI, and Safe Superintelligence - companies largely founded by former OpenAI employees.
Altman later clarified that investors making “non-passive investments” in competitors would lose access to OpenAI’s confidential business information. That’s a real threat. Losing visibility into one of the most valuable private companies in history should matter.
It didn’t. Founders Fund made their first Anthropic investment in February 2026, in the same Series G round. Sequoia had already invested in Anthropic’s Series F in January.
Why the Rules Don’t Apply
The math is straightforward. OpenAI is raising $100 billion at over $850 billion valuation. Anthropic just raised $30 billion at $380 billion. These are the two largest AI companies, and they’re both raising at scales that dwarf most venture portfolios.
When the potential returns are this large, the traditional logic inverts. Not investing in both becomes the risk. If you pick wrong and your competitor picks right, the upside you miss could define your fund’s decade.
Asset managers like D1, Fidelity, and TPG justify their dual positions by pointing out they’re public equity investors making private bets, not traditional venture capitalists with board seats and strategic involvement. That’s technically true but misses the point. The money still flows to both companies.
The most awkward case: BlackRock’s affiliated funds invested in Anthropic’s $30 billion round even though Adebayo Ogunlesi, a BlackRock senior managing director and board member, also sits on OpenAI’s board of directors.
Who’s Staying Loyal
Not everyone has abandoned single-company bets. Andreessen Horowitz backs OpenAI but hasn’t invested in Anthropic. Menlo Ventures backs Anthropic exclusively. These firms may genuinely believe their chosen company will win, or they may be waiting for the right opportunity.
Microsoft’s massive investment in OpenAI ($13 billion and counting) and Amazon/Google’s commitments to Anthropic represent a different kind of loyalty - strategic partnerships where the relationship extends beyond pure financial returns.
But the trend line is clear. The number of dual investors grows with each funding round.
What This Means for the AI Race
The collapse of investor exclusivity has implications beyond portfolio strategy.
First, information flows become murkier. Investors who sit in both companies’ cap table meetings have access to competitive intelligence from both sides. Even with strict ethical walls, the knowledge that your investor is also funding your primary competitor changes the dynamic.
Second, it signals that investors genuinely don’t know who will win. When smart money hedges at these scales, it suggests the outcome is less certain than either company’s valuation implies. A $850 billion company and a $380 billion company can’t both capture the “winner take all” returns that justify their valuations.
Third, it accelerates both companies’ funding capacity. Neither OpenAI nor Anthropic has to compete for a limited pool of exclusive investors anymore. Both can raise from the same mega-funds simultaneously.
The Bottom Line
The AI industry has broken traditional venture capital norms. Companies that would normally be forced to compete for investors are instead sharing cap tables. Firms that would normally pick winners are hedging across rivals.
Whether this is rational portfolio management or a sign of frothy markets depends on your perspective. What’s clear is that the rules that governed tech investing for decades don’t apply to AI at this scale.
Sam Altman told investors not to fund Anthropic. They did anyway. That’s the clearest signal yet that in the AI arms race, even the founders of the biggest companies can’t control where the money flows.