A bit dated but here's cogent explanation: https://www.yishizuo.com/priority-pa...effects/Credit card companies, airlines, and some individuals directly pay one price to Priority Pass. Some of these payments are based on usage, some are based on annual fees.

The company then pays lounges a lower price to provide the service. Sources indicate that the company’s cut is somewhere around 25%. Priority Pass bears little risk while playing a critical role as the middleman.

• Given its structure, Priority Pass enjoys the ability to expand rapidly without having to build physical locations or pay rent to airports.