We propose an unobserved-components-inspired approach to estimate time-varying bargaining power in bilateral bargaining frameworks. We apply the technique to an ex-vessel fish market that changed management systems from a regulated open-access system to an individual fishing quota (IFQ) system over the timespan analyzed. We find that post-IFQ implementation fishers do improve their bargaining power and thus accrue more of the rents generated by the fishery. However, unlike previous studies, we find that fishers do not move to a point of complete rent extraction. Rather, fishers and processors appear to be in a near-symmetric bargaining situation post-IFQ implementation. (JEL C22, L11, Q22)