Venture capital funds have invested hundreds of billions of dollars into a small group of frontier AI labs, with OpenAI and Anthropic alone receiving over 60% of all VC dollars committed to U.S. startups in the first half of 2026, according to PitchBook. This concentration is under pressure from a sudden U.S. tech industry affinity for open-source models, which threatens OpenAI and Anthropic's market dominance. The first major crack came two weeks ago after China's Moonshot AI released its Kimi K3 model, followed by Nvidia CEO Jensen Huang telling Axios that "open-source models that are excellent should be used" and signing a public letter in support of open-weight models, with signatories including Microsoft, Meta and Andreessen Horowitz. OpenAI and Anthropic have pushed back, arguing open-source could prove dangerous, only to be attacked on social media as advocates for regulatory capture. SpaceX, a momentum comp for OpenAI and Anthropic, closed Friday down 49% from its all-time intraday high, 23% below its first trades, and 15% below its IPO price, with shares opening even lower Monday. Hugging Face CEO Clem Delangue said last year that the U.S. tech industry was sleeping on Chinese open-source models and that the "LLM bubble" was close to bursting. Limited partners have tolerated unprecedented concentration, but that could change if frontier fortunes don't materialize.