> They don't do that and none of their competitors do that. Booking.com charges hotels 15% in commission on their sales and that's it. This is how Expedia work

> They don't do that and none of their competitors do that. Booking.com charges hotels 15% in commission on their sales and that's it. This is how Expedia worked for many years. Booking didn't start out doing this, but I think both are now large enough that they all do a bit of both. Some googling suggests Booking may not be buying wholesale directly, but may be just listing inventory from other wholesalers. There's a good episode of the Acquired podcast on Booking.com that goes into some depth on their business model if you want more info.