Legal basis: Article 427 of the Civil Code of People's Republic of China (PRC), combined with the relevant laws and regulations of the Supreme Court on margin pledge, it can be considered that the establishment of fund pledge in margin account must meet the following three conditions at the same time: First, a contract, the contents of which must include the relevant detailed rules for concluding a written pledge. Second, the funds of the deposit must be clearly defined and used for specific purposes. Third, the movable property is transferred to the creditor for possession.