Reinforcement Learning Won Again, This Time With Microsoft

While Microsoft is widely known for backing OpenAI with both infrastructure and capital, the company’s own open-source Phi family of models, part of their own AI research and development, isn’t as recognised the same way.  The Phi series of lightweight models is designed to consume less compute and storage. Thanks to various techniques and optimisation processes involved in the research process, these models have historically outperformed the competition, both in their lightweight segment and even some of the larger ones.  The latest addition is the Phi-4 Reasoning — a 14 billion-parameter model built by applying a supervised fine-tuning (SFT) algorithm to the Phi-4 base model. The researchers also derived the Phi-4 Reasoning Plus model by using reinforcement learning