Open weights

Open weights are the publicly released learned parameters of a trained artificial intelligence model, principally its weights and biases. In an artificial neural network, weights are numerical values that determine how strongly inputs contribute to the network's calculations. Publishing these values allows others to download and use the model, while permission to modify, fine-tune or redistribute it depends on its license. The term is commonly applied to large language models and other generative artificial intelligence models.

As of August 2026, the largest open weights models, with over a trillion parameters, are predominantly released by the AI industry in China, led by Alibaba Cloud, DeepSeek, and AI tigers including Moonshot AI and Z.ai. Open weights releases outside China are led by US labs Thinking Machines Lab, Nvidia's Nemotron family, and French Mistral AI.