Generic drugmaker Mylan Inc said it would buy Abbott Laboratories' specialty and branded generics business in developed markets outside the United States in an all-stock transaction valued at about $5.3 billion. Mylan's shares were up 7 percent in premarket trade after the announcement of the deal that gives it access to Abbott's key products such as gastroenterology drug Creon, pain drug Brufen and influenza vaccine Influvac. The deal has also been structured to help Mylan reduce its tax bill by moving its tax address outside the United States, a practice known as tax inversion that has become popular among healthcare companies. Under the deal, Abbott will transfer the assets to a new public company organized in the Netherlands, after which Mylan will merge with a wholly owned unit of the new company. Abbott will receive 105 million shares of the combined company, giving it about 21 percent ownership stake.