This paper addresses the question as to what extent the outsourcing degrees of property management influence the operating costs of owner-operated real estate. For this purpose, the outsourcing degrees of technical, infrastructural and commercial property management of over 100 Swiss office buildings were reviewed. In terms of costs, the administrative costs as well as the costs of utilities, waste disposal, cleaning, upkeep and maintenance were included. As the analysis of the data revealed, commercial property management primarily impacts on the administrative costs. The office buildings of the four project partners that were examined incurred higher costs when commercial property management was outsourced. Similarly, the costs of utilities and waste disposal are higher for real estate with outsourced infrastructural property management. An inverse relationship was identified in respect of the cleaning costs, where the costs are lower when outsourcing infrastructural property management. The impact of technical property management becomes apparent with regard to the maintenance costs, which are lower for real estate with outsourced technical property management. On balance, the situation appears to be rather heterogeneous, as outsourcing results in higher costs for some cost groups and in lower costs for others. The reasons offered for these differences go far beyond the actual functions being outsourced. For instance, the project partners involved believe that it is, in particular, low service levels and reduced maintenance strategies that go hand in hand with high degrees of outsourcing. Therefore, the interviews with real estate owners, and also the data collected, give rise to the assumption that outsourcing is a measure for the implementation of cost reduction strategies. However, this assumption requires verification by way of further exploration.