Since the years 80 real estate investments are a cross border activity. To day the volume of international investments in the portfolios of Dutch Pensionfunds is about 57 % of the total investments, compared with Gemeany 35 % and teh UK 11 %. Expectations are that diversification of investments across different countries shall grow the coming years. That makes it more necessary to look critically to the reported results of the performance analyses of the concerned properties. At the moment the achieved returns are reported based on the national cultural way the properties are managed and the operational results are justified. Nevertheless there are great differences between those modes of operation. By that an achieved TRR in The Netherlands is not quite the same of one achieved in the UK, Germany, Sweden or France per example. In this paper the results are presented of a survey focused on this issue and based upon the comparison of leased office buildings in named five countries at property as well as portfolio level. It is a plea for introducing one standard for the analyses of pan-European portfolios, beside keeping the national traditions for the home market. So the consequences of cross border investments in real estate can be made more transparant for the international investors.