FrontierMath Was Funded by OpenAI

> We were restricted from disclosing the partnership until around the time o3 launched [...] Our contract specifically prevented us from disclosing information about the funding source and the fact that OpenAI has data access to much but not all of the dataset.

> Regarding training usage: We acknowledge that OpenAI does have access to a large fraction of FrontierMath problems and solutions, with the exception of a unseen-by-OpenAI hold-out set that enables us to independently verify model capabilities. However, we have a verbal agreement that these materials will not be used in model training.

Here, you can read "large fraction" as meaning "everything but the holdout set" - and my understanding is, they haven't disclosed performance on the holdout set.