As in Sweden in general, the municipality owns a large share of the rental multi-family housing stock through itsí housing companies. At present tenants are offered the possibility to buy the houses or the real estate units, from the municipal housing companies, in the form of tenant-owners associations. This extensive process of conversion of tenure will have major influence on the Stockholm housing market, also in respects such as the relationships between residents and between residents and the societyís institutions. The aim of our study is to analyze whether social capital, here in forms of trust and reciprocal norms as well as the resulting collective action and conflicts, changes with conversing tenure. Our hypothesis is that changes will occur and that the tenure form ëtenant-ownerís associationí will imply residentsí stronger participation in decision processes than in rental tenure, which in turn should increase the social capital among residents. On the other hand, factors like increased mobility, due to the opportunity to sell the apartment, or conflicts that may occur between residents who choose to continue renting their apartment and the tenant-ownerís association- can lead to a negative influence on social capital. The data are collected through telephone interviews with residents at two occasions: spring 2008 and spring 2010. Ten buildings in five suburban neighborhoods are chosen for the study, five of which will be, as is indicated right now, owned by tenant-owners associations and five that will continue to be owned by the municipal housing companies. This paper analyzes the results of 350 interviews during spring 2008. Methods used are cross tabulations with Chi-square and Mann-Whitney tests, factor and regression analyses. Results indicate that residents forming tenant-owners associations in order to buy their dwellings have more trust in neighbors in the neighborhood and politicians at local and municipality levels but less trust in the housing company and the neighborhood police than residents that will continue renting their dwellings. Also indicated are local versions of social capital that do not seem to be related to the conversion process.