Legal analysis: whether to prosecute depends mainly on the overdue amount. Generally, if the overdue amount is small, the bank will blacklist the overdue users and may not be able to handle credit business in the future. However, for such a large bad debt of 400,000 yuan, the bank is likely to recover the arrears through legal channels. According to the relevant laws and regulations on credit investigation, if the overdue amount of the cardholder reaches 50,000 yuan, and the cardholder still fails to repay the loan for more than three months after the bank collects it twice, then the credit card user may be sued by the bank.

Legal basis: Article 119 of the Civil Procedure Law of People's Republic of China (PRC) must meet the following conditions: (1) The plaintiff is a citizen, legal person and other organization that has a direct interest in the case; (2) Having a clear defendant; (3) Having specific requests, facts and reasons; (4) It falls within the scope of civil litigation accepted by the people's court and is under the jurisdiction of the sued people's court.