The purpose of this paper is to define and discuss the core-customer concept. This concept examines how a company develops its operations around a single or only a few customers. The customer steers what products and services the supplier develops, which means that it is the customer that dictates the supplier's operations. The core-customer concept may be one method for designing a company's operations, but the paper also aims to challenge companies to consider how they think about customers. The paper contributes to research on customer value and extended service offerings by indicating a business-development strategy based on the customer rather than the supplier's operations. Building a company around a single customer, requires flexibility and competences in finding collaboration partners or in adjusting the organisation to new requirements. The paper refers to these as secondary/supporting competences, while the core competence upon which the company builds its operation is the customer.