To what extent is the observed mispricing in experimental asset markets caused by strategic uncertainty (SU) and by individual bounded rationality (IBR)? We address this question by comparing subjects’ initial price forecasts in two market environments — one with six human traders, and the other with one human and five computer traders. We find that both SU and IBR account equally for the median initial forecasts’ deviation from the fundamental values. The effect of SU is greater for subjects with a perfect score in the Cognitive Reflection Test, and it is not significant for those with low scores.