By Hyun-Seon, Park
Publication Date: 2026-10-20 02:25:00
Microsoft said in an official blog post that it recently completed pretraining of MAI-Base-2, its proprietary large language model (LLM) with 2.8 trillion parameters.
The development marks a move to secure independent AI models and training technologies, shifting away from its previous strategy of relying on OpenAI models.
The new model uses a mixture-of-experts (MoE) architecture across all layers, with 2.8 trillion total parameters and 80 billion active parameters. MoE activates only selected expert networks depending on the input tokens.
Its predecessor, MAI-Base-1, combined dense feed-forward networks with MoE layers. It had 1 trillion total parameters and 35 billion active parameters. MAI-Base-1 served as the foundation for MAI-Thinking-1, a reasoning model Microsoft unveiled in June.
Microsoft said it trained MAI-Base-2 over 38 days in August and September using 16,000 Nvidia GB200 GPUs and a dataset containing 50 trillion tokens.
The…
