The moral intuitions and arguments of some prominent business ethics authors regarding the ethics of monopoly are drenched with contestable economic theory. Discussions too typically ignore theoretical alternatives and debates about the nature of monopolies, their assets and liabilities. I review the theoretical debates and show why they matter to business ethics. That there may be genuine cases of rivalrous monopoly, that monopolies might in the odd circumstance prove more efficient or become advantageous in contests with labor or useful in (...) respect of a nation''s international affairs does not imply we should unwary of monopolies. However, not only the best theory to date, but also the mere fact of serious disagreement in the field suggests that there is no necessary connection between monopolies and practices such as price discrimination, price fixing, bribery, collusion, and so on. This frustrates the most pervasive and most prominent argument so far for the claim that monopolies are intrinsically unethical. (shrink)