The current Chinese leadership that assumed power in late 2012 has launched an anti-corruption campaign that is unprecedented in magnitude. The sheer number of high-level officials cracked down by the Communist Party’s disciplinary body prompts a much speculated question in China studies: how do the dynamics of informal networks affect the Party’s disciplinary punishment of senior cadres? This article initiates the answering of this question with systematic evidence. The authors highlight the threat of rectification campaigns hanging over the bureaucratic system and thus inducing officials to attach themselves to powerful patrons whose protection offers pivotal career security for lower-level clients. Based on the authors’ findings from a sample of over 500 provincial officials in office when the current campaign started, those tied to incumbent members of the Politburo Standing Committee were less likely to be investigated for corruption than those without such ties. Factional ties with retired members of the same body, however, did not provide similar protection. The authors’ analysis helps explain the pervasiveness of personal dependence and factional activities in China’s political system and also sheds light on the complex interaction of informal rules and formal institutions in authoritarian regimes.