The source of the disparity between willingness to pay (WTP) and willingness to accept (WTA) measures of value has been the subject of recent debate in the literature. This paper presents the results of a pilot experiment designed to test whether, contrary to the findings of Shogren et al. (1994), the endowment effect might be a significant source of the WTP/WTA divergence. The results are a direct contradiction of what the substitutability argument would predict and, thus, indicate that the endowment effect cannot yet be dismissed as a possible driving force behind the disparity.