K2 Horizon
A fleet of six fully open AI models from Abu Dhabi's Institute of Foundation Models, ranging from 0.9 billion to 375 billion parameters and published with their training data.
K2 Horizon is a family of six models released in September 2026 under the Apache 2.0 licence. The sizes run from 0.9 billion parameters, small enough to run on a watch, up to a 375 billion parameter flagship built for enterprise work, with phone-sized and laptop-sized options in between. All six share the same architecture and tooling, so you can prototype on a small one and move up without changing how you deploy it.
What sets it apart from most releases called open is that the training data and methodology were published alongside the weights, not just the finished model. That means someone else can in principle check the claims and reproduce the result, which is closer to what open source means in ordinary software than the open weights releases that dominate AI headlines.