How did trusts and holding companies crear unofficial monopolies?

Trusts and holding companies created unofficial monopolies by consolidating control over multiple businesses within a particular industry, often through mergers or agreements that limited competition. By pooling resources and coordinating pricing strategies, these entities could dominate the market, reduce consumer choice, and manipulate supply to maximize profits. This concentration of power allowed them to operate effectively as monopolies without formal legal recognition, often circumventing antitrust laws. As a result, they could stifle competition and maintain high barriers to entry for new firms.