Most of the expertise to develop LLMs is available in research and open-source projects. However, certain aspects are kept as closely guarded secrets.

What is open and shut in case of LLMs are algorithms such as transformers and attention mechanism, the datasets and architecture of the model.

What we can call trade secrets are the fine-tuning techniques the companies use for training it for a specific task, the proprietary software used to give it an edge and the creative use of the model for product development, drug development, protein research etc. Even the exact number of parameters are trade secrets. The training to optimize a model is a close secret. Hardware custom made could be a trade secret.

Though datasets are publicly available, the specific selection of data for training, its cleaning and preprocessing augment the performance of an LLM. Last but not the least, the AI team, the pool of manpower used, makes a difference.

It should be noted that in this developing field, what is trade secret today becomes common knowledge tomorrow.