Welfare Improvement and the Extension of the Income Gap under Monopoly

摘要

This study constructs a model of a monopoly where investors are also actors, and shows that, in contrast to traditional models, this model admits the welfare improvement caused by monopoly. This study also reveals that if a huge income gap exists in the initial stage, then monopoly exacerbates the expansion of the income gap caused by market trades. Moreover, we show that this exacerbation occurs in general situations under some additional (but natural) assumptions.