Who buys and sells olive oil? Who is soy? What is the size of the companies? Is there a group of large companies that have a significant market share? What association, from the agreement or pact, to the merger or absorption, exists between the companies? What is the relationship that unites companies in the sector with large or small banks? What is the incidence of multinationals? What is the trinomial cereals, fats and feed? How much has the cost of collection grown and how does it vary depending on the areas?

The answers to these questions that concern farmers, their cooperatives and their merchants, is the object of this study from a selective approach, because it focuses mainly on the issue of oligopoly, and analytical, because it tries to offer the maximum information available. so that the reader can judge for himself and so that other analyzes and interpretations can be made.