As Chinese AI companies shake the global market with low-cost open-weight models that users can download and modify, U.S. startups are also emerging with open-weight offerings. The Wall Street Journal named Arcee, Reflection AI, Poolside and Thinking Machine Lab as drawing attention. Demand is rising in the United States for domestic open-weight models amid geopolitical concerns, but fundraising remains difficult and performance against leading Chinese models is still uncertain.

Open-source AI models are moving from challengers to the mainstream in the global AI industry. Chinese companies such as DeepSeek, Z.ai and Moonshot AI are releasing open-weight models, and U.S. firms are also joining the trend, putting pressure on closed-model leaders OpenAI and Anthropic. Moonshot AI unveiled its Kimi K3 model, while U.S. startup Thinking Machines Lab introduced its first model as open-weight. The shift is also influencing stock markets and corporate strategies.