“…Hamilton (2009) argues that, for some periods, these estimates are probably good approximations, but, in general, they are subject to instabilities. Studies that have taken the simultaneity of supply-and-demand changes into account, as we do, are scarce -some examples are Alhajji and Huettner (2000), Krichene (2002), Almoguera et al (2011), andLin (2011). We contribute to this literature by estimating a simultaneous dominant firm-competitive fringe model for the oil market, using the nonlinear instrumental variable method -the nonlinear estimator reflects the nonlinearity of the system of equations to be estimated.We obtain statistically significant demand and fringe (non-OPEC) supply elasticities.…”