PITTSBURGH (AP) — The generic drugmaker Mylan is buying Abbott Laboratories’ generic-drugs business in developed markets for stock valued at about $5.3 billion.

Mylan said Monday that the deal will diversify and expand its business outside the U.S. The combined company will be organized in the Netherlands, which will help reduce its tax expenses, while maintaining its headquarters near Pittsburgh.

The deal is expected to lower Mylan’s tax rate to approximately 20 percent to 21 percent in the first full year, and to the high teens after that.

Several other U.S. companies are using mergers to reincorporate in countries with lower tax rates. These moves are raising concerns among U.S. lawmakers since they can cost the federal government billions in tax revenue.

The business to be acquired by Mylan encompasses more than 100 generic and specialty drugs sold in Europe, Japan, Canada, Australia and New Zealand. Some of the products include Creon, Influvac, Brufen, Amitiza and Androgel.

The portfolio of products accounted for about $2 billion in sales last year.

Abbott is keeping its branded generic drug business in emerging markets.

Abbott will own about 21 percent of the combined Mylan company — which will be called Mylan NV — but does not intend to remain a long-term shareholder. Shares of Mylan NV will trade on the Nasdaq under Mylan’s existing ticker symbol, “MYL.”

The transaction is expected to about double Mylan’s revenue in Europe by strengthening its presence in countries such as Italy, the U.K., Germany, France, Spain and Portugal. It also is expected to more than double Mylan’s revenues in Canada and Japan, and strengthen its business in Australia and New Zealand. The deal also gives Mylan a meaningful presence in the specialty and branded generics market in Central and Eastern Europe.

The deal is expected to close in early 2015. It is expected to immediately add to Mylan’s earnings. It is anticipated that the transaction will add about 25 cents per share to adjusted earnings in the first year, increasing through 2018.

Mylan Inc. is based in Canonsburg, Pennsylvania, just outside of Pittsburgh.

Mylan’s stock added $3.27, or 6.5 percent, to $53.47 in premarket trading about two hours before the market opened, while shares of Abbott gained 94 cents, or 2.3 percent, to $42.24 .