Purpose - The purpose of this paper is to explore decision-making from the perspective of different types of investors for future use of vacant offices. The change of the Dutch office market into a buyers’ and replacement market in combination with the continuous overproduction and oversupply, contribute to (structural) vacancy in the real estate portfolios of real estate investors. This vacancy is often the result of a qualitative and quantitative mismatch in the performance of the office building. A well-substantiated decision-making process is essential for investors to make balanced decisions. As such, vacancy management can enhance the decision-making with regard to the future use of office buildings from the perspective of the value-add and core-plus investor. Design/methodology/approach – This paper defines the selection criteria investors use to categorise properties in deprived, mediocre and promising properties. Consequently, the determining criteria and their relative importance for future use of a vacant office building are studied, based upon three partial Delphi studies. These three Dephi studies include criteria on market, location and building level for consolidation, within use adaptation and conversion of an office building. Findings – The results of the Delphi studies are used as input for decision-making about vacancy on portfolio level. Vacancy management enables insight in the qualitative and quantitative (mis-)match of the office portfolio based on the most important criteria on market, location and building level. Practical implications – Possible actions are presented to support decision-making for future use of (vacant) offices for the value-add and core-plus investor. Based on the Delphi studies, buildings are compared and rated to describe the possibilities for different types of future use. Consequently, this paper supports the establishment of a strategy for an (vacant) office building within the portfolio, leading to a practical framework for vacancy management.Originality/value – This paper aims extending existing scientific knowledge by focusing on vacancy management at portfolio level from the perspective of an investor. Vacancy management can contribute to understanding and extending the solution space for problems related to vacant buildings and opportunities for future use of such properties.