The Biggest Stock Brokerage Firms in the United States.
Where Wall Street Goes to School™
The United States has hundreds of stock brokerage firms, but a handful dominate the industry due to their size, reputation, customer service, digital platforms, and the sheer volume of assets they manage. While many firms compete in the brokerage space, four companies have consistently remained at the top: Charles Schwab, TD Ameritrade, Fidelity Investments, and E*TRADE.
With Schwab’s recent acquisition of TD Ameritrade, these four will eventually consolidate into three major players. Each firm offers a mix of brokerage accounts, financial products, retirement accounts, advisory services, and online trading tools — but each also maintains a unique identity within the industry.
Below is a closer look at the largest brokerage firms in the U.S., how they rose to prominence, and what sets each apart.
What Do Brokerage Firms Actually Do?
A brokerage firm helps investors buy and sell financial products, such as:
- ETFs and mutual funds
- Stocks and options
- Bonds
- Retirement accounts (like IRAs)
- Advisory and wealth management services
Most brokerage firms also provide:
- Customer service support
- Online trading platforms
- Mobile apps
- Research tools
- Account management features
Today’s top firms must balance offering discount brokerage services (such as low or zero commissions) with full-service brokerage features (like advisory services and wealth management). This combination is why large firms attract millions of clients and manage trillions in assets under management.
1. Charles Schwab
As of June 30, 2019, Charles Schwab managed an impressive $3.7 trillion in assets across nearly 12 million brokerage accounts. Schwab is widely recognized as a leader in both traditional and modern brokerage services.
One of Schwab’s biggest advantages is the size of Charles Schwab Bank, one of the largest banking subsidiaries in the U.S. This gives Schwab the ability to link brokerage accounts with checking accounts — something many discount brokerage firms cannot match. It appeals to customers who want a unified financial experience.
Schwab offers:
- Proprietary investment products
- Third-party financial products
- Commission-free stock and ETF trades
- A robust trading platform
- Strong research and customer service
In 2019, Schwab announced zero-commission trading, a major move that reshaped the entire brokerage industry. This shift forced other firms to eliminate or reduce fees, making trading more accessible for retail investors.
Schwab’s Acquisition of TD Ameritrade
In late 2019, Schwab announced it would acquire TD Ameritrade. Because both firms were massive, the process required extensive regulatory review. Once fully integrated, Schwab will gain Ameritrade’s trading tools, including the well-known Thinkorswim platform, strengthening Schwab’s position among both beginner and advanced investors.
2. TD Ameritrade
TD Ameritrade, which will soon merge into Schwab, began as Ameritrade and grew significantly through acquisitions. In 2006, Ameritrade acquired TD Waterhouse USA, rebranding to TD Ameritrade. In 2017, Ameritrade expanded again by acquiring Scottrade, another well-known brokerage firm.
Today, TD Ameritrade manages over $1 trillion in assets and serves more than 11 million client accounts.
TD Ameritrade is known for:
- 24/7 customer service
- Advanced trading platforms
- Strong research tools
- Educational resources for new and experienced investors
- A user-friendly website and mobile app
The firm carved out a niche in customer experience. It was especially attractive to active traders because of its charting tools, options trading capabilities, and powerful interface.
Although Ameritrade will eventually operate under Schwab’s brand, its legacy — especially the Thinkorswim platform — continues to shape the industry.
3. Fidelity Investments
Fidelity Investments is not only a major brokerage firm; it is also the largest provider of 401(k) and 403(b) retirement plans in the United States. This gives Fidelity a unique leadership position in long-term investing and employer-sponsored retirement accounts.
As of September 30, 2019, Fidelity reported:
- $7.8 trillion in assets
- 72 million accounts
- 30 million individual investors
Fidelity offers clients:
- ETFs and mutual funds
- Managed retirement accounts
- A wide range of financial products
- Third-party investments
- Industry-leading customer service
Beyond its brokerage accounts, Fidelity manages tens of millions of additional customers through its mutual funds and advisory services. This makes Fidelity more than just a discount broker — it is a full-service financial institution with deep expertise in both personal investing and retirement savings.
Its emphasis on research tools, educational content, and investor guidance has helped Fidelity stay competitive even as more firms turn to zero-commission models.
4. E*TRADE
While E*TRADE is smaller than the other three major firms, it remains one of the most recognizable names in online trading. E*TRADE built its reputation by focusing on digital accessibility long before mobile trading became mainstream.
Features that made E*TRADE stand out include:
- A strong mobile trading app
- Easy-to-use online platform
- Options trading capabilities
- Retirement accounts and brokerage accounts
- A range of ETFs, mutual funds, and financial products
ETRADE struggled during the 2008 financial crisis due to exposure to subprime mortgages, but it eventually recovered and rebuilt its position in the market. Today, ETRADE is known as a convenient platform for both new and experienced investors.
Full-Service vs. Discount Brokerage Firms
The U.S. brokerage industry includes two broad categories:
Full-Service Brokers
These firms offer advisory services, wealth management, retirement planning, and portfolio guidance. Fidelity and Schwab operate hybrid models, offering both advisory and self-directed accounts.
Discount Brokers
These firms focus on low-cost or commission-free trades, online brokers, and easy access. E*TRADE and TD Ameritrade gained popularity by reducing friction and offering powerful digital tools.
Today, nearly all major firms operate hybrid models, combining discount brokerage services with value-added research, customer service, and financial planning tools.
Why These Firms Dominate the Industry
These companies lead the market because they provide:
- Massive assets under management
- Strong customer service
- Broad ranges of financial products
- Integrated banking and brokerage accounts
- Competitive pricing (often zero commissions)
- Advanced digital tools and mobile apps
- Strong reputations and decades of industry presence
Their scale allows them to invest in technology, offer better pricing, and provide resources that smaller brokerage firms cannot match.
As the industry continues to consolidate — especially with Schwab absorbing TD Ameritrade — these firms will likely remain the dominant players influencing customer expectations and market trends.