(S)ubsidiarity, by virtue of its emphasis on devolving power away from concentration among the few (whether bureaucrats or businessmen), encourages the sort of competition and diversity that may well be both the greatest help to the poor and the best guarantor of economic stability, and it promotes the kinds of checks and balances that provide efficient, sensible regulation.
The Catechism states: “The principle of subsidiarity is opposed to all forms of collectivism. It sets limits for state intervention. It aims at harmonizing the relationships between individuals and societies. It tends toward the establishment of true international order.”
Read all of Subsidiarty – A Primer.