You Now Have to Be 21 to Buy Cigarettes in San Francisco by John Kell @FortuneMagazine March 2, 2016, 10:30 AM EDT E-mail Tweet Facebook Linkedin Share icons San Francisco become the second-largest U.S. city to raise the age to legally purchase tobacco from 18 to 21, a move that comes a few years after a similar move by New York City. The Associated Press reports that San Francisco supervisors – the legislative branch of the city – voted on Tuesday to boost the legal age to buy cigarettes and other tobacco products, including e-cigarettes. In addition to New York City, Hawaii and Boston also require tobacco buyers to be 21. Investors shrugged off the news, as shares of the nation’s largest cigarette makers – Altria mo and Reynolds American rai were trading only slightly down on Wednesday. The goal of the higher age requirement, San Francisco asserts, is to discourage young people from turning into lifelong smokers. An estimated 40 million U.S. adults were cigarette smokers, according to the Centers for Disease Control and Prevention, which says tobacco remains the single largest preventable cause of death and disease in the U.S. The move by San Francisco again proves what industry analysts have long known about New York City: the city often drives tobacco legislation changes that permeate into other areas of the country over time. In 2003, for example, New York enacted the Smoke-Free Air Act, at the time controversial legislation as it banned smoking in the city’s bars and restaurants. That action was subsequently followed by many cities and states.