After signing an account with a local bank, you need to go to the bank for "tripartite custody". The so-called "three-party custody" should be "third-party custody" accurately. In other words, ordinary investors must open trading accounts in securities companies, and both investment funds and trading securities are "deposited" in securities companies. Objectively, it constitutes the "two sides" existence of general investors and service providers (brokers).

However, brokers are both service providers and direct participants in securities trading. In this case, some brokers use the "margin" of clients' funds and securities to misappropriate clients' funds and securities for their own profits, which has caused many problems and adverse consequences. Up to now, there are still some "problem" brokers who have not completely solved the sequelae.

In order to prevent and correct various irregularities in the management of clients' investment funds, China Securities Regulatory Commission has made special provisions on the management of clients' investment funds. The client's investment funds must be "third-party custody" by the bank where the securities company opens an account (generally only two banks can be selected), which means that the securities company can no longer directly manage the client's funds.