WP4 focuses on examining political corruption in policymaking and political finance, exploring how undue influence is exerted through lobbying and campaign financing. It aims to map the mechanisms of such influence in parliaments and regulatory bodies, creating a dataset on political donations, including their origins and potential fraud risks. The compendium of common methods for bypassing lobbying and finance regulations will be developed through case studies and workshops, shedding light on the actors and strategies involved in these practices. A key aspect of this WP is the analysis of how political finance, particularly private donations, influences government spending and benefits key constituents, particularly by studying incumbent behavior and its link to corruption. The project will also investigate how digital tools can improve transparency, tracking donations and illicit finances. Furthermore, WP4 will assess the effectiveness of different regulatory and institutional conditions in either enabling or curbing corrupt practices, drawing on data from other work packages and case studies to explain corruption risks in public procurement, legislation, and electoral outcomes.