More than a dozen family members of China's top political and military leaders are making use of offshore companies based in the British Virgin Islands, leaked financial documents reveal. The brother-in-law of China's current president, Xi Jinping, as well as the son and son-in-law of former premier Wen Jiabao are among the political relations making use of the offshore havens, financial records show. The documents also disclose the central role of major Western banks and accountancy firms ... in the offshore world, acting as middlemen in the establishing of companies. The Hong Kong office of Credit Suisse, for example, established the BVI company Trend Gold Consultants for Wen Yunsong, the son of Wen Jiabao, during his father's premiership - while PwC and UBS performed similar services for hundreds of other wealthy Chinese individuals. The disclosure of China's use of secretive financial structures is the latest revelation from "Offshore Secrets", a two-year reporting effort led by the International Consortium of Investigative Journalists (ICIJ), which obtained more than 200 gigabytes of leaked financial data from two companies in the British Virgin Islands, and shared the information with the Guardian and other international news outlets. In all, the ICIJ data reveals more than 21,000 clients from mainland China and Hong Kong have made use of offshore havens in the Caribbean. Between $1tn and $4tn in untraced assets have left China since 2000, according to estimates.