Regulators in Hong Kong and mainland China have launched a coordinated crackdown on offshore investment accounts, impacting millions of mainland investors. On May 22, the Hong Kong Securities and Futures Commission (SFC) issued a circular highlighting deficiencies in account opening procedures at 12 securities brokers, citing risks of illegal transactions and money laundering. New requirements mandate written declarations from mainland clients affirming that their funds originate overseas. Simultaneously, the China Securities Regulatory Commission, along with eight other ministries, introduced a two-year plan to govern illegal cross-border securities activities. This plan restricts existing accounts to asset sales and fund transfers only, prohibiting new accounts or deposits. Major brokers like Futu Securities and Tiger Brokers have ceased accepting new mainland clients, while others have tightened compliance checks. Despite these restrictions, some compliant channels remain open for mainland investors, including Stock Connect and QDII. However, the crackdown signals a significant tightening of regulations, closing long-standing loopholes and emphasizing the need for compliance in cross-border investments.