Another two-letter .COM domain looks to be off the market forever after California-based Ubiquiti Networks stealthily acquired the UI.com domain name, upgrading from the four-letter domain UBNT.com. Ubiquiti, founded in 2005, is a publicly-listed technology company that achieved revenues of $1.016 billion in 2018, with a net income of over $196 million. At the time of publishing, the company's stock price is listed at around $166, up sharply from the start of the year when it achieved a price of $99.31 per share. It seems as though Ubiquiti purchased the name at the end of 2018, according to DomainIQ's WHOIS history, which noted a change in nameservers. Ubiquiti clients noticed this change earlier in the year, with several threads popping up on Ubiquiti's own forums and Reddit. Interestingly, the current WHOIS listing for the domain shows that it is under privacy protection at GoDaddy, but since Ubiquiti has switched to using UI.com, it's a sure sign that they have indeed purchased the domain. The company hasn't publicly confirmed the switch from UBNT.com to UI.com, but the four-letter name now redirects to UI.com, and UI.com is now listed as the company's main domain name on Wikipedia. According to WHOIS history, Mike Gleissner was the previous owner of the name. To domain investors, that name might be familiar since he's also listed as owning domains such as Q.net. Archival versions of the UI.com domain show that during 2018, the name displayed a website for UI Advertising. Having briefly looked through Ubiquiti's SEC filings, I can't find any mention of the UI.com domain name, but it's highly likely that the domain fetched a significant price. In 2007, the name sold for $275,000 at Afternic. Thanks to @MadAboutDomains for the information.