Arcee AI Releases Trinity, a 400B-Parameter Open Source Foundation Model Built by 30-Person Startup

Summary

Arcee AI, a 30-person startup led by CEO Mark McQuade and CTO Lucas Atkins, released Trinity on January 28, 2026 — a 400-billion parameter open source foundation model released under the Apache license. Trinity is described as one of the largest open source foundation models from a U.S. company, competitive with Meta's Llama 4 Maverick 400B and Z.ai's GLM-4.5 on benchmarks. The release is notable for several reasons. First, a 30-person team building a 400B-parameter model from scratch demonstra