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.

Four teams in the government-backed \"sovereign AI foundation model\" project have completed preparations for a second-round review, industry sources said. Two large companies have built models with more than 600 billion total parameters, comparable in size to major global open-weight models. Two startups opted for models of around 300 billion parameters, focusing on compute efficiency and task execution. All four use a mixture-of-experts structure and are pursuing different approaches to scaling up.