The Communication and Information Techniques sector reveals an unstable environment. The managers of small and medium-size firms respond to this kind of environment by using decision-making biases. In this study, we propose to study two biases (insider bias and self-serving bias) particularly efficient on network performance. The insider bias describes the strong tendency to consider problems as unique, focusing on the case at hand without considering the context. The self-serving bias consists in a tendency to attribute positive incomes to a self. Two case studies are chosen for their emblematic perspective. The qualitative results show strong support for two proposals. First a natural network of clients is embedded thanks to a central firm which analyses the environment with an inside view. Second the self-attribution of the first success has negative impacts on building familial networking
