According to a 2009 U.S. State Department communication by Hillary Clinton, United States Secretary of State, (disclosed as part of the Wikileaks U.S. 'cables leaks' controversy in 2010) donors in Saudi Arabia constitute the most significant source of funding to Sunni terrorist groups worldwide. Part of this funding arises through the zakat (an act of charity dictated by Islam) paid by all Saudis to charities, and amounting to at least 2.5% of their income. Although many charities are genuine, others allegedly serve as fronts for money laundering and terrorist financing operations. While many Saudis contribute to those charities in good faith believing their money goes toward good causes, it has been alleged that others know full well the terrorist purposes to which their money will be applied.