Rights theory argues that all individuals have fundamental rights and privileges. Even if an action such as sweatshop labor is legal, it may violate fundamental rights and be unethical.
Justice theory focuses on a just distribution of economic output. Under a "veil of ignorance" managers lacking all the necessary information are charged with making ethical decisions requiring difficult tradeoffs. This theory is based on the premise that as long as there are gains to all parties involved this is a legitimate way of making ethical decisions. Justice theory recognizes unequal divisions of wealth and income may be acceptable under the differencing principal, which holds the unequal division must benefit the least advantaged members of society.
Milton Friedman addressed the social responsibility of business which touches on the issue of business ethics by stating that as long as the business has followed all applicable laws then it has met its obligation to the employee.
Utilitarianism argues that businesses must weigh the consequences to society of each of their actions and seek to produce the highest good for the largest number of people.
Kantian ethics argues that people are different from other factors of production, they are more than just an economic input and deserve dignity and respect.