本研究探討廠商從事策略性或利他性的環境企業社會責任時，對消費者關心產品環保品質的綠色覆蓋市場的影響，並且將廠商的產品環保品質水準分為內生和外生的兩種情況下，探討廠商對環境的關心程度會如何影響廠商的產品決策。 在雙占垂直差異模型中，當廠商從事純策略性或是利他程度較低的環境企業社會責任時，我們發現只有高環保品質產品廠商才會投資產品環保品質，但其最適產品環保品質水準低於社會最適水準，這意味著環境受到較少的保護。當廠商的總體利他性環境企業社會責任程度上升到一定水準時，低環保品質產品廠商也會進行產品環保品質的投資，兩家廠商的產品環保品質最適水準均有所提高，甚至高環保品質產品廠商其環保品質可能高於其社會最適水準，因此環境可能會被過度保護。其中有趣的是，當廠商加強對環境的關心程度時，其利潤都會隨之減少，表示兩家廠商的利潤在其具有利他性環境企業社會責任時皆被犧牲了。 ;This study investigates the impact of firms′ strategic and altruistic corporate environmental responsibility (CER) engagement on a covered green market where consumers care about green quality. Divides firms′ green quality levels into two cases: endogenous and exogenous, and discuss how the firm′s concern for the environment will affect the firm′s product decision. In a duopoly vertical differentiation model, we find that only the greener firm invests in green quality, when firms engage in pure strategic or sparsely altruistic CER. The environment is less protected because firms′ optimal green quality levels are below the social optimum. When firms′ aggregate altruistic CER engagement rises to a certain level, the less green firm also invests in green quality. The firms′ optimal green quality levels will improve, and even the greener firm’s optimal green quality level may be above the social optimum, so the environment may be over-protected. Interestingly, when firms increase their concern for the environment, their profits decrease, indicating that the profits of both firms are sacrificed when they have altruistic CER.
