What term refers to the joining of businesses that operate in exactly the same line of business?

The term that refers to the joining of businesses that operate in exactly the same line of business is horizontal integration. This strategy involves companies at the same stage of production or in the same industry merging or acquiring each other to increase market share, reduce competition, or achieve economies of scale. For instance, if two competing manufacturers of smartphones were to merge, they would be engaging in horizontal integration.

Vertical integration, in contrast, involves companies at different stages of production in the same industry joining forces, such as a manufacturer acquiring a supplier or distributor. Synergy refers to the idea that the combined value and performance of two companies will be greater than the sum of the separate individual parts, but it does not specifically define the relationship between companies in the same industry or line of business. Integration is a broader term that encompasses all forms of business combinations but doesn't specify the type or relation of the companies involved.