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Last week, two billionaires—Microsoft founder Bill Gates and New York City mayor Michael Bloomberg—announced their latest plan for spending some of their vast fortunes. The pair, through their respective charitable organisations, the Bill & Melinda Gates Foundation and Bloomberg Philanthropies, will contribute a combined total of US$500 million to global tobacco-control programmes.

This is not the first time that Bloomberg, who led New York City's successful anti-smoking legislation in 2002, has contributed his own money to anti-tobacco efforts. In 2005, he set up Bloomberg's Initiative to Reduce Tobacco Use with $125 million, and his foundation helped fund WHO's Report on the Global Tobacco Epidemic 2008. That report culminated in the MPOWER package, a group of evidence-based strategies for tobacco control. (The acronym stands for: Monitor tobacco use and policies; Protect people from second-hand smoke; Offer help to quit; Warn about the dangers of tobacco; Enforce bans on advertising, promotion, and tobacco company sponsorship; and Raise taxes on tobacco products.) Bloomberg will now make a further donation of $250 million, to be used over 4 years. The Gates' contribution is $125 million over 5 years, of which $24 million is designated as a grant to the Bloomberg Initiative. These investments are modest when set against the net worth of the two funders, but the amount vastly exceeds what is now being spent on tobacco control in low-income and middle-income countries. According to the 2008 WHO report, such spending comes to less than half a penny per person per year—against tobacco tax revenues of nearly $66 million.