A merger is an event or an act when two or more entities come together to form one entity or company. A merger can take place either by way of one entity absorbing the other or by closing the old units and constituting a one new entity. There can be horizontal as well as vertical mergers. Horizontal mergers take place with the coming together of two different companies within a single industry. However, a merger is said to be vertical when two companies from varying industries come together to form a single entity.