Background: The Supply Chains of both the oil & gas as well as the construction industry are recognized as complex networks. Therefore, the coordination of these Supply Chains calls for strategic approaches. Procurement and the application of purchasing strategies are one of the decisive aspects for a companies’ business performance and its competitive advantage. Category management and in particular the lead buyer concept are strategic approaches, which help companies to diversify the strategies according to its product portfolio. However, so far little insights are provided about these two industries with regard to the purchasing strategies and the lead buyer concept.  

Purpose: The purpose of this thesis was to analyze the role of procurement/purchasing within Supply Chain Management. In specific, procurement, the influences of purchasing strategies over time as well as the role of the lead buyer within a company’s purchasing activities.

Method: Within this thesis a multiple case study approach was applied. The cases presented in this thesis consist of two different companies active in the oil & gas as well as construction industry. This thesis made use of primary as well as secondary data. Primary data was gathered through 7 semi-structured interviews and observations. Secondary data was collected through a literature review and documentary secondary data. The empirical findings were structured according to themes and finally, cross-case analysed with regard to literature.

Conclusion: This thesis highlights the importance of strategic purchasing and further examines the contribution of applying the lead buyer concept. A company can increase its Supply Chain competitive advantage and enhance its performance by choosing the strategy according to its needs and goals. The positive influences can occur within short- or long-term. The implementation of the lead buyer concept can help companies in various ways. It allows the company to apply an efficient purchasing process, exploit the different advantages of the lead buyer and to choose the most appropriate purchasing strategy.