Dear Friend,
One of the chief reason for the increase in Mergers and acquisition in the present day world is Synergy. There are other reasons such as increasing the scale of operation, increasing market share, entering a new market, utilizing the tax benefits etc.
If we are looking into few present day examples such as Kingfisher purchasing shares in Air Deccan- it is because the routes served by Air Deccan and Kingfisher are complimentary tio each other so they can very well organise connection flights etc and also Air Deccan will get the license to operate international flights shortly whereas Kingfisher have to wait a couple of years for that. So the Kingfisher can utilize its facilities to operate the international flights by Air Deccan.
The acquisition of Corus Steel by Tata Steel is to increase its international presence and its share in the international market.
The acquisition of Gujarat Ambuja Cements by Holcim was for getting into our country.
Hope some of your doubts are cleared.
Thank you
regards
Manoj Pillai