They further explained that the regulations are different in different regions according to the local legislation regulations and in United States (the largest market) there is no control on the price of sale of non-government drugs, but in Canada, the situation is entirely opposite and legislation have control on the prices of drugs from other countries as well. In the year 2010, the five big giants of the industry accounted almost 50% shares in total sales of the year with the following share in sales; Pfizer Inc. (12.2%), GlaxoSmithKline (11.0%), Johnson & Johnson (8.9%), Merck and Co., Inc. (7.5%), and Sanofi-Aventis U.S. LLC (7.0%). The situation leads the companies towards the alliance to work together in order to deal with threats of competition and research and development. Economists and business authors have defined merger and acquisition as “when companies deal with each others to buy, sell, and combine or to divide in different entities”. The major alliance in the form of merger and acquisition was the acquisition of Wyeth by the big name of Pfizer in pharmaceutical industry. In this essay we will analyze the strategic and financial aspect of the deal so that we can find out the reasons and answers of some important questions like why Pfizer acquired Wyeth and why Wyeth sell out its business to Pfizer etc. According to the official website of Pfizer October 15, 2009 Pfizer Inc. acquired Wyeth in a cash and stock. The deal was signed in $68 billion. The main points of the deal according to the terms and conditions was, each outstanding share of Wyeth common stock has been converted into the right to receive $33 in cash (without interest) and 0.985 of a share of Pfizer common stock according to the Editor of businesswire.com (2012).