the impact of green technology investment (ecolabeling), in a duopoly model of vertical product differentiation. The firms … for both firms is always positive, but lower than in the duopoly solution. In the absence of environmental externalities …

duopoly equilibrium when convex costs of quality provision are either fixed or variable in terms of production. We show that … optimal under variable costs. In the duopoly equilibrium the quality spread is too wide under variable costs, but too narrow … provided by the duopoly equilibrium is too low from the perspective of a social welfare maximizer. …