Japan Tobacco said on Tuesday it will buy the Natural American Spirit brand outside the United States for roughly $5 billion from Reynolds American. The transaction is expected to be completed by early 2016, JT said in its statement. Japan accounts for the majority of the brand's sales volume outside the United States, JT added. Japan Tobacco is one of the world's biggest tobacco companies whose international brands include Winston and Camel. But it has suffered lacklustre domestic sales, as Japan's once huge number of smokers shrinks. Japan Tobacco has looked at international markets for growth potential, and made international headlines for the 2007 purchase of Britain's Gallaher for almost $19 billion.