China has begun enforcing a long-overlooked tax on overseas investment gains made by the country's ultra-wealthy individuals, according to a Bloomberg report. Wealthy residents in major cities have been asked to assess their tax liabilities or summoned by tax authorities to evaluate potential payments, including arrears from previous years. The move underscores the government's urgency to expand revenue sources amid slowing economic growth and declining land sales. It aligns with President Xi Jinping's "common prosperity" campaign to reduce wealth inequality. Individuals face up to 20% levies on investment gains and possible penalties for overdue payments. The enforcement follows China's adoption of the Common Reporting Standard in 2018, enhancing global tax transparency.