Based on the combined perspective of the transaction cost theory (TCT), the resource-based view (RBV) and the extended resource-based view (ERBV), this thesis presents an analysis of the influence of identified potential determinants of vertical integration on backward integration with suppliers through mergers and acquisitions (M&A). The objectives of the work are to identify and examine determinants that may have an impact on backward integration through M&A and to create a conceptual model that can be used to explain and examine the determinants of such integration through M&A. Drawing on an extensive literature review, six hypotheses were derived. These test the relationship between the determinants of vertical integration, namely asset specificity, environmental uncertainty, transaction frequency, closeness of competences, the VRIN criteria of the supplier, and the VRIN criteria of the supplier's supplier base, and backward integration through M&A. An empirical, quantitative study was conducted in the form of a self-administered online questionnaire addressing the research aim of the thesis. This was sent to managers and decision-makers, who included procurement managers, supply chain managers, chief procurement officers, and supply chain-related consultants. The survey ultimately reached 445 potential respondents and 122 responses were received. The statistics support the positive and significant impact of asset specificity and closeness between the buyer’s competences and those required for a specific activity performed by a supplier. The study contributes to the literature by showing that together ERBV, RVB, and TCT contribute to research on the determinants of vertical integration. The constructs examined, particularly asset specificity and closeness of competence, are ones that predict the suitability of M&A with suppliers within the context of vertical integration. The results are also of relevance for practitioners, helping them to consider and appropriately assess such influencing factors when making decisions about company boundaries.