In markets where dealers play a central role, bid-ask spreads inhibit asset valuation as defined by the formation cost of a replicating portfolio. We introduce a nonlinear valuation formula similar to the usual expectation with respect to the risk-adjusted probability measure. This formula expresses the asset's selling and buying prices set by dealers as the Choquet integrals of their random payoffs We investigate several price puzzles: the violation of the put-call parity and the fact that the components of a security can sell at a premium to the underlying security (primes and scores). Copyright 1996 Blackwell Publishers.

International audienceEmployee ownership is often used not only as a reward management tool but also as an entrenchment mechanism. The literature suggests that good managers use employee ownership as a reward management tool, whereas bad managers implement it for entrenchment, thus suggesting the existence of an equilibrium level of employee ownership. The contributions of this paper are both theoretical and empirical. Theoretically, this paper fills a gap in the published research by taking into account both positive and negative outcomes of employee ownership. Our model produces three main conclusions: (i) Low-performing managers use employee ownership as an entrenchment mechanism (ii) that increases the signaling cost of employee ownership for high-performing managers. (iii) We suggest that employee ownership should not be left only to the management's discretion because both types of managers have an incentive to implement employee ownership. Our empirical study investigates how employee ownership affects management tenure. This study takes into account the two main motives for employee ownership examined by the model (i.e., management entrenchment and reward management). We find a positive relationship between employee ownership and management tenure. This result provides new evidence that employee ownership can be used as an entrenchment mechanism