A call for mainland leaders to disclose their personal assets as a safeguard against conflicts of interest and corruption in government was first made at the National People's Congress 18 years ago, long before former president Jiang Zemin pushed for the inclusion of private entrepreneurs in the Communist Party. The idea has been repeated frequently since with little effect. Now, in the wake of the downfall of Bo Xilai , the emerging extent of his business interests has given new weight to the matter. Without transparency, the marriage of politics and wealth can be an unholy alliance that breeds corruption. China is a case in point. To give the issue context, one American news service recently cited figures in the Hurun report, which tracks China's wealthy, to make a comparison with the United States. It found that the net worth of the 70 richest delegates to this year's NPC was US$90 billion, after rising last year by US$11.5 billion. That is more than the US$7.5 billion total wealth of all 660 top officials in the three branches of the US government. Obviously there are fewer wealthy businessmen among those US officials. But even if the actual figures are open to debate, such concentration of wealth, political influence and institutional power has worrying implications for society, despite China's success in eradicating poverty. Other countries have official corruption issues regardless of political systems. That is why they maintain registers of pecuniary interests, declarations of assets and the like, with safeguards for privacy consistent with the public interest. Since the detention of Bo and his wife Gu Kailai the issue of rampant official corruption on the mainland has become more urgent. Indeed, top leaders have often said that it poses a threat to the party's political legitimacy. Premier Wen Jiabao has frequently pushed for a system of public disclosure of officials' assets, without any real progress. But effective ways to reduce corruption are not difficult. One that reflects Wen's ideas is Taiwan's 'sunshine' laws, which compel government officials, including the president and their spouses and dependants, to publicly declare all their assets at home and abroad annually. Such declarations as there are by mainland officials are submitted to superiors and are not open and transparent. As a supposed safeguard, that is more likely to institutionalise corruption. There is no substitute for publicly accessible and accountable declarations for officials and close relatives. If revealing everything overnight is seen as too big a reform to undertake in one step, officials could at least make sworn declarations to party members appointed as custodians. The coming change of top leadership is an opportunity for new leaders to set the example by declaring their own and their relatives' assets. Aspiring leaders would find it difficult not to follow.