Digitalization has generated massive amounts of available data sources (Wedel and Kannan 2016). Consequently, firms aim to exploit this additional value – particularly in decision-making (Barton and Court 2012). However, potential misleading consequences of Big Data for companies have not been examined yet – neither in practice nor in research. Addressing this research gap, the current investigation first uncovers questionable managerial outcomes and behaviours generated by Big Data. The results of a first paper-and-pencil experiment show that executives tend to rely on Big Data even in a domain where this may be misleading (i.e., innovation) (Martin and Golsby-Smith 2017). Interestingly, this relationship is found to be particularly evident for top-managers. A second online study does not only replicate the findings in a correlational setting but beyond sheds light on its mechanism. We show that Big Data activates top-executives’ promotion focus leading them to become more risk seeking and egocentric. In study 3, we replicate these findings through experimentation and moderation underlining its robustness. Finally, we detect a lever to avoid that Big Data leads to less defensive decision behaviour (study 4).