OpenAI CEO Sam Altman.

It looks like Sam Altman just acquired a four letter URL worth more than $15 million.

On Wednesday, the OpenAI 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 cofounder of CRM platform HubSpot, who wrote on LinkedIn in 2023 that he paid an “8 figure sum” for it.

At the time, Shah wrote that it was “the most expensive domain name transaction I’ve ever been involved with,” saying he bought the domain name because he believes chat-based software is the next big thing. He also added he would not be using the domain name for his own company and would sell it if a buyer appeared.

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

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

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

In a tongue-in-cheek ChatGPT-style prompt in his post, Shah seemed to imply that he did not profit off the domain sale and likely took some OpenAI shares as payment. He stated in the prompt-like passage that he has known Altman for 10 years and doesn’t like to profit off of his friends.

OpenAI did not immediately respond to Fortune’s request for comment.