Pope John XXIII
Mater et Magistra §35
Mater et Magistra: On Christianity and Social Progress
35 Pius XI was not unaware of the fact that in the forty years that had supervened since the publication of the Leonine encyclical the historical scene had altered considerably. It was clear, for example, that unregulated competition had succumbed to its own inherent tendencies to the point of practically destroying itself. It had given rise to a great accumulation of wealth, and, in the process, concentrated a despotic economic power in the hands of a few "who for the most part are not the owners, but only the trustees and directors of invested funds, which they administer at their own good pleasure.'' (l4)
Source: Mater et Magistra (Vatican.va)