The article examines why companies choose to merge in industries where different firms make similar products. When one company merges vertically (integrates), it forces its rival's production costs to rise, affecting the quality of their goods. The merging firm always makes the best product first, earning more money. Overall, quality investments from both companies decrease in merged industries, leading to less competition among them. The result is a fully integrated industry with a variety of products, ultimately increasing company profits and social welfare compared to no integration.