Many would argue, reasonably so, that OpenAI is now a de facto subsidiary of the largest company in the world by market cap, Microsoft (Apple is second and Saudi Arabian Oil is third).
I read this comment as "NVIDIA just took over Saudi Aramco" and was briefly confused in what could possibly be their reasoning for that acquisition?! Perhaps they decided to get some weird lower price on fuel for their gpus.... Anyways it was a brief but fun bit of confusion.
To be fair, this is the time for NVIDIA to leverage their stock and buy up shit to diversify because their stock is going to correct eventually lol. So why not buy out a oil producer ahaha.
The value of Saudi Aramco can't really be trusted. It's listed on their own stock market which the company controls. It has no reporting requirements, and the float is a single digit percent of the company.
It would be the same as me creating my own market, issuing 10,000,000,000 shares, and then convincing 1000 people to buy a share at $100 and then claiming my company is worth $1T.
I think it's unknowable but most likely overvalued. It is in their best interest to convince everyone that it is more highly valued than it is as they try to diversify. Look at the recent investor gathering they had in Florida. People were desperate to get their attention, even people who have strong political disagreements with them. That only happens because everyone assumes they have a lot of money to invest.