Comment by singron

I think it makes the most sense this way, but I've seen it accounted for in other ways. E.g. if free users produce usage data that's valuable for R&D, then they could allocate a portion of the costs there.

Also, if the costs are split, there usually has to be an estimation of how to allocate expenses. E.g. if you lease a datacenter that's used for training as well as paid and free inference, then you have to decide a percentage to put in COGS, S&M, and R&D, and there is room to juice the numbers a little. Public companies are usually much more particular about tracking this, but private companies might use a proxy like % of users that are paid.

OpenAI has not been forthcoming about their financials, so I'd look at any ambiguity with skepticism. If it looked good, they would say it.