The objectives of this study were to analyse: (i) efficiency gains that a municipality would gain by publishing accounts payable data as open data; and (ii) socio-economic effects with a major focus on democracy aspects. Summarising, we can state that potential efficiency gains related to opening accounts payable data can be significant, which was also confirmed by previous studies. Based on experience of Swedish municipalities publishing accounts payable as open data, we have made an estimation of potential efficiency gains due to reduced time to answer inquiries coming from citizens, journalists, and organisations. Based on these assessments, the potential efficiency gains may reach approximately 2 million kr per year for large municipalities. Additionally, availability of open data on accounts payable may result in further reduction of time needed to handle an inquiry due to opportunity to direct a person to thee open data file, a more exact and specific question formulation, and reduced number of inquiries. It was found that democratic aspects in publishing accounts payable were perceived as more important than potential time savings and efficiency gains. This is especially important for smaller municipalities, which do not get that many inquiries and cannot expect the same level of savings effect. Democracy aspects are closely related to transparency, openness, and opportunity to push procurement prices down. All this leads to even greater savings for municipalities. Another important aspect is finding mistakes and discovery of corruption cases. Elimination of such cases in the future would result in considerable savings at national level. One of the important findings of this research is the fact that municipalities already publishing open data do not see any related risks, while municipalities that are only preparing to publish open data see a number of risks related to open data publishing. The major concerns are related to confidentiality, privacy, and secrecy risks, unclear quality of data, and increased workload for some units. We also make a number of recommendations from different perspectives, which could accelerate the process of open data publishing. This analysis was carried out by Tatjana Apanasevic from RISE Research Institutes of Sweden as a part of Nationell Skalning Öppna Data (NSÖD) project, financed by Vinnova. The analysis is based on primary data collected through interviews with seven municipalities (the City of Gothenburg, the City of Lidingö, Skövde, Varberg, Karlskrona, Uppsala, and Skellefteå), a service provider, consultants working with open data, and three (data) journalists.