The global education reform movement has led to the development of quasi-markets and the promotion of business-like operation of schools with the goal of improving education for students and opportunities for teachers. While many types of schools have been influenced by marketisation, the international school market is a prime example of how such processes can be fully integrated into education. However, despite the prevalence of market reforms, little is known of their impact on educational employees. This research investigates the perspectives and experiences of teachers in compulsory-age international schools operated by large multi-national for-profit education management organisations to understand how business-like operations within a school market affect their daily work. Semi-structured interviews were used to create items to measure the business influences. Scales were then developed with Mokken Scale analysis and Rasch analysis. The two scales demonstrate distinct patterns of marketisation. The scale of direct business influences on teachers' work includes items on competition between schools, increasing admissions and improving finances, while the scale of indirect influences includes items about job insecurity, hierarchical organisational structures, fear of repercussions when voicing professional opinions, and an emphasis on evidence of learning. Notably, these quantitative patterns were consistent across many different types of schools, both for-profit, non-profit private schools and government schools. These findings demonstrate the strength of researching teachers' experiences to understand the impact of marketisation on education.