On Wednesday, OpenAI’s CEO ominously tweeted a simple URL, chat.com, which is now the new home of his company’s flagship AI tool, ChatGPT.

The new URL was previously owned by Dharmesh Shah, the co-founder of CRM platform HubSpot, who wrote on LinkedIn in 2023 that he paid an “8-figure sum” for it.

Shah wrote at the time that it was “the most expensive domain name transaction I have ever been involved in,” and said he bought the domain name because he believes chat-based software is the next big thing. He also added that he would not use the domain name for his own business and would sell it if a buyer emerged.

“Chat.com is absolutely brilliant in terms of simplicity, brevity and being completely *on point* and meeting the moment,” Shah wrote at the time.

But just a few months later, Shah said he sold the domain without specifying who the buyer was. He said at the time that he took $250,000 of the proceeds from the sale and donated it to Khan Academy, a nonprofit educational organization.

After Altman’s tweet, Shah confirmed that OpenAI had purchased the domain name, which he said he bought for $15.5 million. As for the price OpenAI paid for the URL, Shah was deliberately vague.

In a tongue-in-cheek ChatGPT-esque prompt in his post, Shah seemed to suggest that he didn’t profit from the domain sale and likely took some OpenAI stock as payment. He stated in the prompt-like passage that he has known Altman for a decade and does not like to take advantage of his friends.

OpenAI did not immediately respond Fortune‘s request for comment.