Types of Merger

There are various types of merger.

Horizontal merger : Combination of two firms in the same line of business. Horizontal merger is more often lately.  Examples are Pfizer's 2009 acquisition of Wyeth and Bank of America's acquisition of Merill Lynch. Horizontal merger is usually intended to reduce costs and achieve economies of scale.

Vertical merger : Combination of two firms at different stage of production. The buyer expands back toward the source of raw materials or forward in the direction of ultimate consumers. One way to achieve this is to merge with a supplier or a customer. Example is 2008 acquisition of Tele Atlas by its fellow Dutch firm, Tom Tom. Tom Tom wanted to use Tele Atlas's digital map data to provide real-time updates on its sat-nav system. Another example is Google's acquisition of Double-Click.
Nowadays the tide of vertical integration seems to be flowing out. Companies are finding it more efficient to outsource the provision of many service and various types of production.

Conglomerate merger : Combination of two firms in unrelated line of business. The principal mergers of the 1960s and 1970s were mostly conglomerate. Conglomerates are much less popular at least in developed countries.


Supplementary Information
ファイザー＆ワイス：
ファイザーはワイス買収により抗うつ剤「エフェクサー」や肺炎予防ワクチン「プレブナー」を獲得し、年間売上高は46％増の700億ドル程度となる。コレステロール降下剤「リピトール」が後発医薬品（ジェネリック）との競争にさらされる2011年以降に見込まれる収入減の影響を和らげるのに役立つ。買収金額はUSD64.5 billion。


TomTom & Tele Atlas：
２００７年カーナビのTomTomが地図サービスのTele Atlasを買収。買収金額は２０億ユーロ。買収により、より正確なナビゲーション情報の実現と、事業領域の拡大、新機能の追加や拡充などが見込めるとしている。


グーグル＆ダブルクリック；
２００７年３０億ドルでダブルクリックを買収。ダブルクリックは、CNETやESPN.comといったコンテンツサイトにディスプレイ広告の配信や効果測定サービスを提供していた。Googleが広告を売り、ダブルクリックが広告を届けることを目的とした買収。