Today, Pfizer (PFE) has announced that it will combine with Allergan (AGN) in a $160 billion deal or $363.63 per Allergan share. Allergan shareholders are getting 11.3 shares of the combined company for each of their Allergan shares, and Pfizer shareholders are getting one share of the combined company for each Pfizer share. 

The combined company is expected to trade on the NYSE under the name of Pfizer PLC, with the ticker of PFE. One of the reasons Pfizer made this deal was so that it could relocate its headquarters to Ireland to take advantage of tax inversion. Pfizer will make its principal executive office in Ireland, because of this but its global headquarters will still be in New York. 

As soon as the deal closes, Pfizer estimates that it would save up to $2 billion on this deal over the course of the next three years. The combined company will make the largest pharmaceutical company to date as it will be expected to generate up to $25 billion in operating cash flow by 2018. This merger is expected to close by the 2nd half of 2016.

First, Allergan must finish selling its generics business to Teva (TEVA) in the first quarter of 2016. In addition this merger is also dependent upon other customary closing conditions such as: Regulatory approval in both countries, and agreement from Pfizer and Allergan shareholders. Pfizer shareholders will have the option to receive cash instead of shares of the combined company.