Why MNCs goes to or transfer capital to tax havens

This is a very essential bangla reading in respect of understanding on how and why MNCs goes to or transfer capital to tax havens. Strange that now even IMF also telling this, as because now developed / OECD countries are also sufferer in this regard, along with developing countries. Please see the link

http://www.bonikbarta.com/2014-06-30/news/details/5986.html