Marriott’s new room assignment system—which they officially call the Automatic Complimentary Upgrade (ACU) system—is not powered by a third-party AI like OpenAI or Google. Instead, it’s an in-house machine learning system developed within Marriott’s own tech division.

Key details:

It was designed and piloted by Marriott’s internal AI lab, as part of their broader digital innovation initiatives dating back to 2023

The system uses proprietary machine learning algorithms to evaluate millions of room allocations daily—considering factors like elite status, arrival times, past survey scores, and guest preferences—and continuously refines its decision-making using feedback loops

It automates the upgrades process for Bonvoy Gold and above, running each upgrade “at 3 PM the day before arrival,” based on current inventory and the hotel’s definitions of what qualifies as an upgrade

So, Marriott isn’t relying on AWS, Azure, or OpenAI—they’ve built, trained, and refined their own AI platform tailored specifically for room assignment and upgrade decisions.