The concentration of income and wealth is, for the bishops, not something that happens haphazardly. As they write in paragraph 69, this happens “primarily through the mechanisms of the financial system.”
They criticize the lack of limits on financial investments and the resulting lack of concern for long-term goals and emphasis on short-term profit.
The freedom granted to financial investments favors speculative capital, which has no incentives to make long-term productive investments, but rather seeks immediate profit in transactions with public bonds, currencies, and derivatives.
Citing the Compendium of the Social Doctrine of the Church, paragraph 334, they press for an economy of solidarity and the common good:
The economy has as its object the development of wealth and its progressive increase, not only in quantity but also in quality; this is morally correct if it is directed to man’s overall development in solidarity and to that of the society in which people live and work. Development, in fact, cannot be reduced to a mere process of accumulating goods and services. On the contrary, accumulation by itself, even were it for the common good, is not a sufficient condition for bringing about authentic human happiness.
Finally they call for social responsibility by businesses:
Business is called to make a greater contribution in society, assuming from this perspective, what is known as social-business responsibility.
Here is the USCCB translation of the 2007 document from the Aparecida Conference.