What is the term for a merger between two companies of roughly equal size?

The term for a merger between two companies of roughly equal size is a merger of equals.

Unlike a conventional acquisition, a merger of equals is presented as a combination in which neither company is clearly the buyer. The companies may exchange shares, share board representation, and negotiate leadership and ownership arrangements intended to reflect comparable standing.

The phrase describes the deal’s structure and perception, not necessarily a mathematically exact 50–50 combination. In accounting, even transactions called mergers of equals are generally treated as business combinations, and one company may still have to be identified as the acquirer for reporting purposes.

A common mix-up is “consolidation,” which is a broader legal term for combining entities and does not specifically emphasize similar size or shared status. A joint venture is different again: it usually creates a jointly controlled business while the original companies continue to exist independently. An acquisition, by contrast, normally identifies one company as obtaining control of another.