Mandatory profit sharing can represent a Pareto-improvement if labour supply is excessive due to relative consumption effects. Profit sharing reduces wages. If the rise in profit income keeps total income constant, there will only be a Pareto-improving substitution effect.

I study the evolution of reciprocity in a gift-exchange game. In equilibrium, wage offers induce maximal effort but there is strong inequity in favor of the workers. The result suggests that norm-based efficiency wages may be unstable over time.