Companies choose to merge with other companies for many reasons. First of all, mergers offer synergies and economies of scale. They can provide you with access to new products, to new markets or boost your market share and your authority (power). By merging with another company, companies are able to reduce the competition which shrinks the margins and reduces the profits. In addition, buying a successful company can have less risks that trying to start a new company or a new product from scratch. Of course, mergers can also go wrong! They are a lot of cases where the result was not what was expected due to different companies cultures, failure to organise and operate a larger organisation (more complex entity) or due to other reasons as well.