Nathan Lambert announced on X that his time at Ai2 had ended after more than two and a half years working on open models including Olmo and Tülu. A longer Interconnects post identifies June 1 as his last day.
Lambert said he plans to keep working in open models and open science. His current personal site says he is founding a stealth AI lab, but he has not disclosed its name, so the destination remains unspecified in Turing Tree.