AsianFin -- Interactive Brokers Group (IBKR), the world’s largest online brokerage, has introduced stricter requirements for mainland Chinese residents seeking to open securities accounts, as Beijing intensifies efforts to clamp down on offshore tax avoidance.

Since last month, IBKR has toughened its onboarding procedures for new mainland clients, and its mobile app has been removed from app stores in China. According to the company’s website, applicants must now submit a mainland identification document along with proof of overseas residency or employment covering the past three months in order to be approved.

The move comes as Chinese tax authorities step up enforcement of overseas income taxation, putting pressure on investors who had turned to U.S. brokerages such as IBKR to sidestep information-sharing obligations under the Common Reporting Standard (CRS).

While more than 100 jurisdictions, including China, participate in the CRS — which mandates the automatic exchange of financial account data — the United States does not. Instead, Washington enforces its own Foreign Account Tax Compliance Act (FATCA). The gap has fueled speculation among some investors that U.S. brokers provide a loophole to avoid mainland regulators’ scrutiny of offshore holdings.