While research on information systems (IS) project control has advanced considerably over the last decade, knowledge about the performance effects of particular combinations of control modes is still limited. In this study, we add an important piece to the puzzle of control effects and control mode interaction. We do so by examining the impact of informal control on project performance as well as whether formal controls moderate the effectiveness of informal control in IS offshoring projects. We conducted a quantitative study with data from 46 projects involving 16 client firms from a wide range of industries. Our results suggest that clan control in combination with outcome control positively influences project performance. In contrast, the exercise of clan control alone does not increase performance. Our study thus offers an important contribution towards uncovering the links between formal and informal control modes. It also highlights the importance of carefully tuning control portfolios in IS offshoring projects. Restrictions and requirements for how clan control can be leveraged in the offshore context are discussed.