The concern to create cleaner and more ecosystem-friendly production processes has extended to the parking sector in Spain. Since the creation of the multi-level institutional framework for sustainable mobility management (mainly composed of the Infrastructure, Transport and Housing Plan 2012–2024, the Sustainable Urban Mobility Plans, Law 9/2006, and Law 9/2017), environmental considerations, including sustainable management certificates, have occupied a privileged place in public procedures for the management of parking structures and regulated surface parking facilities. Although there have been previous academic studies on the design and implementation of SUMPs and the growth of the parking sector, this article is novel in that it analyzes the market concentration of the parking sector in a scenario where climate change policies are crucial and the importance of sustainability certificates takes on a new meaning. Therefore, the objective of this article is to analyze whether the growing importance of environmental aspects has led to an increase in the concentration level of the parking sector in Spain. For this purpose, several concentration and stability indices are calculated. The results show that, although there are additional factors, the certification of a cleaner activity is relevant in the process of public tenders in the sector, which has served to strengthen the dominance of the most prominent companies in the sector that are in possession of environmental certificates. This shows that environmental policies can also have negative effects on the market, so the results of this analysis are of great value to policymakers.