The proliferation of fact-checking services is a fast-growing global phenomenon, especially in Western countries. These services are the response of journalism to disinformation, that has transformed a common internal procedure of journalistic work in the core of a business directed to the general public, also offered to the companies of mass media and social media. Literature review shows that the research on fact-checking has focused on the origin, funding, relationship with the media, procedures, and experiences related to politics and COVID-19. However, the ownership structure of the fact-checking services has been superficially analysed and the business model of these platforms has not yet been studied in detail and depth. The objective of this article is to identify and analyse the business model of the nine Spanish active fact-checking services through a documentary research of public information sources and the information that these services give about themselves. This paper explains their ownership structure and income provenance, from open information sources. The findings are that the fact-checking services that depend on media groups are no strangers to the trend of opacity usual in these groups, but in the case of fact-checking services that are born as initiatives of journalists, the trend towards transparency is, in the majority of cases, clear. However, the information provided by the Spanish fact-checking services is deficient and does not allow us to discover their business models, except in the case of Newtral and, to a certain extent, Maldita.