Disney-21st Century Fox ($71 Billion, 2019)

Disney’s $71.3 billion acquisition of 21st Century Fox gave it control over 40% of the US box office, instantly creating an entertainment superpower and triggering monopoly concerns. The deal led to 4,000 layoffs in the first year alone, erasing Fox's identity. This concentration of market power is six times higher than the industry average for media mergers, far exceeding the competitive disruption of #7 Amazon-Whole Foods.