This is not investment advice. The information provided is for educational and informational purposes only and does not constitute a recommendation to buy or sell any financial product.
A custodian, in the context of a stock trading account, is the entity that holds the trader's securities separate from the broker. The separation is required by the regulator in most jurisdictions, and the protection is real. The trader's cash and securities are held in segregated accounts at the custodian, and the custodian is a different legal entity from the broker. If the broker fails, the trader's assets are held by the custodian, and the trader can transfer the assets to another broker.
What a custodian does
The first job of the custodian is to hold the securities. The custodian maintains a record of the trader's holdings, and the custodian is responsible for the safekeeping of the securities. The custodian is a regulated entity, usually a tier-one bank or a specialist custodian, and the custodian is subject to the same regulatory oversight as the broker.
The second job is to settle the trades. When a trader buys a stock, the custodian receives the shares from the seller's custodian and credits them to the trader's account. When a trader sells, the custodian debits the shares and credits the cash. The settlement process is usually T+1 or T+2 in major markets, and the custodian is the entity that handles the settlement.
The third job is to handle corporate actions. When a stock in the trader's account pays a dividend, the custodian credits the dividend to the trader's cash balance. When the stock splits, the custodian adjusts the trader's position. When the company is acquired, the custodian handles the cash or stock consideration. The custodian is the entity that manages the corporate actions on the trader's behalf.
The fourth job is to provide the statements. The custodian provides the monthly statement, the annual statement, and the tax reporting. The statements are the trader's primary record of the holdings, and the statements are the basis of the trader's tax filing.
Why the separation matters
The separation matters because it protects the trader's assets in the event of the broker's failure. The broker holds the trader's cash and securities in a segregated account at the custodian, and the assets are not part of the broker's estate. The trustee of the failed broker can return the assets to the trader, or the trader can transfer the assets to another broker, and the transfer is usually smooth.
Without the separation, the trader's assets would be part of the broker's estate, and the trader would be a general creditor of the broker. The general creditor's claim is at the bottom of the priority list, and the recovery is usually much lower than the trader's claim. The trader who holds assets with a broker that is not subject to the segregation rules is exposed to a real risk of loss in a broker failure.
The separation is required by the regulator in most jurisdictions. The regulator sets the rules for segregation, and the broker is required to comply. The rules vary by jurisdiction, but the principle is the same: the trader's assets are held separately from the broker's assets, and the trader has a direct claim on the segregated assets.
How the custodian is chosen
In most cases, the broker chooses the custodian, and the trader does not have a say. The broker has an agreement with a tier-one bank or a specialist custodian, and the broker places the trader's assets at the chosen custodian. The trader's only choice is to choose a broker that uses a reputable custodian.
The choice of custodian is a function of the broker's business model. A full-service broker usually uses a tier-one bank as the custodian, and the bank is a separate legal entity from the broker. A discount broker may use a tier-one bank, a specialist custodian, or a sub-custodian in a foreign market. The trader's only verification is to check the broker's documentation for the custodian's name and the segregation rules.
A second choice is to use a broker that offers multiple custodian options. Some brokers offer a choice of custodian, and the trader can choose the custodian that fits the trader's needs. The choice is usually between a tier-one bank (with higher fees and stronger protection) and a specialist custodian (with lower fees and slightly weaker protection). The trader should weigh the trade-off before choosing.
The case for a separate custodian
A separate custodian is useful when the trader wants a stronger segregation of the assets. The trader who holds a large portfolio, with significant assets at risk, may want a separate custodian that is not affiliated with the broker. The separate custodian charges a fee, and the fee is the cost of the stronger protection.
A separate custodian is also useful when the trader wants to use a specific custody arrangement. A trader who holds assets in a foreign market may want a sub-custodian in that market, and the sub-custodian is the entity that holds the assets in the local jurisdiction. The sub-custodian is usually a tier-one bank in the foreign market, and the sub-custodian is subject to the regulator in the foreign market.
The case against a separate custodian is the cost. The separate custodian charges a fee, and the fee is a real drag on the return. A trader with a small portfolio is usually better off with the broker's default custodian, and the trader pays a small fee (or no fee) for the segregation. A trader with a large portfolio is the one who benefits from the stronger protection.
How to verify the custodian
The honest answer is to ask the broker. The broker is required to disclose the custodian, and the disclosure is usually in the account opening documentation. The trader can also check the broker's website, and the trader can confirm the custodian's regulatory status on the regulator's website.
The second answer is to read the segregation documentation. The broker is required to provide documentation on the segregation rules, and the documentation explains how the trader's assets are held, what the protection is, and what the recovery path is in the event of the broker's failure. The trader should read the documentation before funding the account.
Related resources
Where to start
If you are choosing a broker, the most useful exercise is to check the custodian, the segregation rules, and the recovery path. Our broker comparison lists the broker's custodian and the segregation policy, which together tell you what the protection looks like before you fund the account.