They're independently owned. You could argue that it was just accounting if the two businesses had the same or similar ownership while being two separate entities, but they're two different publicly traded companies with substantially different ownership. They also don't share a single board member. Can you provide some sort of substantive indication that they're operating together (today, as compared to prior to the TripAdvisor spinoff)?

For context, here's where you can see the substantial differences in ownership: https://finance.yahoo.com/quote/TRIP/holders/ vs https://finance.yahoo.com/quote/EXPE/holders/ .

And here's where you can see that they share no board members: http://ir.tripadvisor.com/corporate-governance/board-of-dire... vs https://www.expediagroup.com/about/leadership/ .