NEW YORK (TheStreet) -- Drugmaker AbbVie is raising its takeover offer for Irish pharmaceutical company Shire for a fourth time to $51.6 billion, an 11% increase from its prior bid, as it seeks a tax inversion deal.
Under the new offer, AbbVie raised its cash-and-stock bid by 11% to more than $51 billion. Shire already rejected AbbVie's previous bid of $46 billion, saying it significantly undervalued the company.
As part of the deal, AbbVie would acquire Shire and move the combined company's tax home to the U.K., which has a main corporate tax rate of 21%, below the U.S. federal corporate tax rate of 35%. AbbVie has said it would see its overall tax rate cut to 13% by 2016 as a result of the acquisition and inversion.
Shire did not immediately reject the offer, saying its board would meet to consider the proposal. Under British law, AbbVie has until July 18 to make a formal offer to acquire Shire or step away from a deal for up to six months.
In New York, I'm Brittany Umar for TheStreet.
-- Written by Brittany Umar in New York.