Either way, compression nights are incredibly important to the hotel industry. UBS estimates that hotels make anywhere from 35% to 70% more revenue per available room (RevPAR) during sold-out nights because of the steep premiums they can charge. But in two of Airbnb’s biggest markets—New York and San Francisco—UBS says the number of compression nights declined in 2015, even as US hotel occupancy hit record highs. UBS analysts think that’s because travelers faced with exorbitant rates at hotels are just turning to Airbnb instead.