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The Largest Online Brokers by AUM

Toni Nasr, CFA, FRM| Updated November 3rd, 2022

Brokerage firms have been in existence for several decades and have evolved to provide a wide range of services to their clients. At a high level, each broker may operate differently, for example, focusing on a specific asset class, market segment (retail or institutional), or geography. Furthermore, due to the vast number of platforms available today, determining the best online broker can be difficult.

Certain key metrics, such as Assets Under Management (AUM), number of customers, customer ratings, number of regulators, and others, are applicable to almost any brokerage or asset management firm, and can help you have a clearer picture of the security or reputation of the firm.

Here’s the list of the top online brokers by Assets Under Management (AUM):

Largest Online Brokers by AUM in 2022

With over $9.9 trillion in assets under management, Fidelity is the largest online broker worldwide. In second place, Vanguard AUM stands at $8.1 trillion. A large portion of those assets is related to investments in their mutual funds, and the majority of their investors are clients of other brokerage firms who invest in these funds.

In terms of users, Fidelity has over 40 million users. Interestingly, eToro, which has a lower AUM at nearly $10 billion, has over 30 million users. This can be attributed to the international expansion eToro has done over the years and its social trading features.

What are Assets Under Management (AUM)?

In general, AUM refers to the market value of assets managed by a company on behalf of its clients. This metric is used by different financial institutions such as mutual funds, hedge funds, insurance companies, and brokerage firms. It is a key performance indicator that measures the success of a firm in attracting customers and increasing its market share.

The definitions and calculations for AUM can vary by company. For example, funds deposited with the company but over which the company has no discretionary authority are typically excluded from the calculation. In this case, assets under administration are calculated, where the service provider does not have discretion over the asset allocation decisions and the clients manage their funds directly. In this study, we listed the brokers with data related to AUM. If it was not available, we checked their clients’ assets or Assets Under Administration.


AUM changes over time due to market fluctuations or clients’ withdrawals, and it is usually updated on a quarterly basis. A higher AUM does not imply that the broker has better services than others, or alternatively, a lower AUM does not necessarily indicate a less trustworthy broker. 

Each broker has its own unique features that differentiate it from its competitors, such as fees, minimum balance requirements, or trading platform. Still, not all customers are eligible to open an account at one of the above-mentioned brokers since some brokers limit their services to particular regions. We encourage investors to check the company’s financial statements and website, and do their due diligence about the services and opportunities before opening an account with any broker.

Toni Nasr, CFA, FRM
Fintech Analyst

Toni is a Fintech Analyst with over 8 years of experience in the financial industry where he worked as a financial control analyst at a regional bank and later conducted independent investment research analysis.