Party funding regulation is a way to level the playing field of electoral competition and preventing political corruption. Research in this area has mainly analyzed party funding regulation as a variable that affects different aspects of the party system. However, recent theoretical and empirical research suggests analyzing factors that drive party funding regulation. Based on the seminal study by Scarrow (2004), two main set of interests have been discussed as drivers of regulation in this field: the ‘revenue-maximizing’ logic and the ‘electoral economy’ one. Evidence from in-depth case studies has been provided to confirm either the first or the second perspective, without conclusive results. Even in the same country, evidence from both sets of driven forces have been found when analyzing different party funding reforms processes over a specific period of time (Piccio, 2014). This urges us to shed light on other individual and contextual factors that may have an impact in the decision to create either ex novo regulation or reform existing regulation aimed to increase transparency in the party funding system. In this study, we use quantitative data to analyze the interest of the incumbent party to reform party funding regulation. Three theoretically-driven factors are analyzed as independent variables: (1) oscillations experienced by the incumbent party in its own funding structure in a yearly-basis; (2) oscillations in the economic competition between the incumbent party and the main opposition party in a yearly basis; and (3) political leadership of the incumbent. Exact Logistic Regression is applied to analyze these three variables in the Spanish context. Our results show that the probability for the incumbent party to be interested in reforming regulation increases as the opposition party gets more annual revenue than he does, and as his political leadership is under threat.
