Best Online Brokers for Index Funds in 2025

Investing in index funds is one of the most reliable ways to build wealth over the long term. But where you choose to invest matters as much as what you invest in. The right online broker can help you maximize your returns through low fees, strong fund access and tools that support passive investing strategies.

Long-term investors have more options than ever before. But not all brokers are created equal, especially if you’re focused on minimizing costs, accessing popular fund families like Vanguard, Fidelity or Schwab and taking advantage of features like dividend reinvestment and automatic investing.

Quick Look at the Best Online Brokers for Index Funds:

• Best Overall: Fidelity Investments
• Best Customer Service: Charles Schwab
• Best for Direct Access to Low-Cost Funds: Vanguard
• Best for Automation and Custom Portfolios: M1 Finance
• Best for Beginners: SoFi Invest
• Best for Research Tools: E*TRADE
• Best Bank-Integrated Broker: Merrill Edge

How We Chose the Best Brokers for Index Fund Investors

Our evaluation focused on what truly benefits a passive, long-term investor:

• $0 commissions for index fund purchases
• Access to major fund families (Vanguard, Fidelity, Schwab and others)
• Retirement account options including traditional and Roth IRAs
• Dividend reinvestment programs (DRIP) and automatic investing features
• Transparent expense ratio information and fund comparison tools
• Educational resources aimed at building long-term investing knowledge

All brokers listed meet a high accessibility standard, transparency and cost efficiency which are the key pillars of successful index fund investing.

Best Online Brokers for Index Funds in 2025

Choosing the right broker for index fund investing isn't just about low fees, it's about finding a platform that supports your long-term strategy with the right tools, fund access and account options. Here’s a closer look at the top brokers leading the way in 2025.

Best Overall: Fidelity Investments

Fidelity Investments continues to lead the industry for index fund investors. With $0 commissions across all mutual funds and ETFs plus access to their own Fidelity ZERO funds (which carry no expense ratio at all), Fidelity sets the standard for low-cost investing. Its retirement accounts including IRAs, Roth IRAs and solo 401(k)s allow for automatic investing, dividend reinvestment (DRIP) and extensive long-term planning tools.

Fidelity’s mobile app and web platform offer detailed fund screeners, retirement calculators and free webinars for investors who want to explore passive investing strategies more deeply. Whether you're building your first portfolio or rolling over a 401(k), Fidelity makes it simple and cost-effective.

Minimum Investment for Index Funds: $0
DRIP Available: Yes
Index Fund Access: 10,000, including Fidelity ZERO funds
Retirement Accounts: IRA, Roth IRA, Solo 401(k)

Best Customer Service: Charles Schwab

Charles Schwab remains a top choice for passive investors who value service just as much as pricing. Schwab offers commission-free access to its full suite of proprietary index funds (many with expense ratios under 0.03%) and also allows trading of Vanguard, Fidelity and other fund families. Investors can open no-minimum IRAs and set up automatic contributions and dividend reinvestment easily.

Schwab’s support tools include screeners, long-term investing calculators and live advisor access for help with portfolio construction accessible without sacrificing flexibility. Some third-party mutual funds outside Schwab’s OneSource program may still carry transaction fees, so fund selection matters.

Minimum Investment for Index Funds: $0 for Schwab funds (varies for third-party)
DRIP Available: Yes
Index Fund Access: Over 3,000
Retirement Accounts: IRA, Roth IRA, 401(k) rollovers

Best for Direct Access to Low-Cost Funds: Vanguard

Vanguard practically invented the modern index fund and it remains a best-in-class choice for investors who want direct access to low-cost funds like VTSAX or VFIAX. Vanguard offers $0 commissions for online trades of its own mutual funds and ETFs, alongside automatic investing and reinvestment options.

While Vanguard’s user interface feels more functional than flashy, its dedication to low fees and client-owned structure firmly align investor interests. If you’re serious about long-term investing and willing to deal with a slightly clunky app, Vanguard still delivers unmatched fund access at rock-bottom costs.

Minimum Investment for Index Funds: $1,000 –$3,000 (varies by fund)
DRIP Available: Yes
Index Fund Access: More than 100
Retirement Accounts: IRA, Roth IRA, SEP IRA

Best for Automation and Custom Portfolios: M1 Finance

M1 Finance offers a unique hybrid between robo-advisors and self-directed platforms, making it ideal for passive investors who want control but don't want to micromanage. Investors can build customizable “Pies” which are combinations of ETFs and index funds and automate contributions, rebalancing and dividend reinvestment at no extra cost.

M1 charges no commissions or account management fees for basic accounts and it supports Traditional, Roth and SEP IRAs for long-term retirement savings. While M1’s trade windows run only once or twice daily (not instant execution), that limitation encourages a disciplined, long-term investing approach.

Minimum Investment for Index Funds: $100
DRIP Available: Yes
Index Fund Access: Offers 6,000+ stocks and ETFs listed on the NYSE and NASDAQ exchanges
Retirement Accounts: IRA, Roth IRA, SEP IRA

Best for Beginners: SoFi Invest

SoFi Invest is built for investors just starting, offering zero commissions, no account minimums and free access to licensed financial advisors. Investors can access low-cost index ETFs from providers like Vanguard and Schwab or choose SoFi’s automated investing portfolios with no management fees.

SoFi’s app-based platform is straightforward and educational, featuring tutorials and articles for first-time investors. For new savers looking to build a passive index fund portfolio without feeling overwhelmed, SoFi makes an easy and effective starting point.

Minimum Investment for Index Funds: $5
DRIP Available: Yes (in automated portfolios)
Index Fund Access: Over 6,000 no-transaction-fee mutual funds
Retirement Accounts: IRA, Roth IRA

Best for Research Tools: E*TRADE

ETRADE balances powerful research tools with commission-free access to thousands of no-load mutual funds and index ETFs. Investors can filter by expense ratio, asset class and fund family to quickly find options that fit their long-term strategy. Dividend reinvestment and retirement accounts (IRA, Roth IRA, SEP IRA) are standard offerings and ETRADE's educational content caters to investors who want to fine-tune their portfolio allocations.

If you're looking for a deeper data dive while still sticking to passive investing principles, E*TRADE offers the flexibility and resources that serious planners will appreciate.

Minimum Investment for Index Funds: For prebuilt portfolios of mutual funds, the minimum investment is $500 and for ETFs, it's $2,500
DRIP Available: Yes
Index Fund Access: 5 no fee Index Funds
Retirement Accounts: IRA, Roth IRA, SEP IRA

Best Bank-Integrated Broker: Merrill Edge

Merrill Edge offers a strong blend of zero-commission trading, excellent integration with Bank of America banking products and access to preferred rewards programs for high-balance clients. Investors can trade Vanguard and Fidelity index ETFs commission-free, access pre-built portfolios and automatically reinvest dividends through Merrill’s DRIP service.

Merrill Edge also offers retirement account support and in-depth research tools, making it a practical choice for long-term investors especially those already managing finances through Bank of America.

Minimum Investment for Index Funds: $0
DRIP Available: Yes
Index Fund Access: More than 2,800 ETFs and just under 3,000 mutual funds
Retirement Accounts: IRA, Roth IRA, rollover 401(k)

Your Index Fund Strategy

Finding the right broker is about more than just zero commissions. Long-term investors need a platform that offers reliable fund access, cost transparency, retirement account options and automation tools that make sticking to a passive strategy easy.

• If you want the lowest possible cost: Fidelity or Vanguard lead the way.
• If you value tech and ease of use: M1 Finance or SoFi may be better fits.
• If you want broad service and strong flexibility: Schwab is a top choice.

Whichever platform you choose, remember the basics: keep your fees low, stay diversified and stay the course. Index investing rewards patience and choosing the right partner will make the journey that much smoother.

Frequently Asked Questions