Looking to invest in a diversified fund without a steep price tag? Enter low-cost index funds and ETFs. These funds offer a basket of securities for a very minimal fee.
Top-rated low-cost index funds
The lowest-cost index fund may not be the best-performing index fund. When evaluating index funds, consider other factors, such as market capitalization and sector focus.
Our methodology: To arrive at our list, we filtered for index funds with the lowest expense ratios that have at least $10 billion in assets and a Morningstar rating of at least 4 stars.
Ticker | Fund name | Expense ratio |
|---|---|---|
FZILX | Fidelity ZERO International Index Fund | 0.000% |
FNILX | Fidelity ZERO Large Cap Index Fund | 0.000% |
SSEYX | State Street Equity 500 Index II Portfolio | 0.010% |
FXAIX | Fidelity 500 Index Fund | 0.015% |
SWPPX | Schwab® S&P 500 Index Fund | 0.020% |
FSMDX | Fidelity Mid Cap Index Fund | 0.025% |
FSPGX | Fidelity Large Cap Growth Index Fund | 0.035% |
Source: Morningstar. Data is current as of July 1, 2026, and is intended for informational purposes only, not for trading purposes. | ||
How free index funds work
Fidelity is one of very few brokers that offer access to no-expense-ratio index funds. The other is E*TRADE. The catch is that you need a brokerage account with these companies to access them.
Top-rated low-cost index ETFs
Some of the cheapest index funds out there are actually exchange-traded funds (ETFs). ETFs often track indexes just like index funds do, but they tend to have lower investment minimums (the amount of money you have to have in order to start investing in a fund).
Our methodology: To arrive at our list, we filtered for U.S. equity ETFs with the lowest expense ratios that have at least $10 billion in assets and a Morningstar rating of at least 4 stars.
Ticker | Fund name | Expense ratio |
|---|---|---|
SPYM | State Street® SPDR® Portfolio S&P 500® ETF | 0.020% |
VO | Vanguard Mid-Cap Index Fund ETF Shares | 0.030% |
VB | Vanguard Small-Cap Index Fund ETF Shares | 0.030% |
VUG | Vanguard Growth Index Fund ETF Shares | 0.030% |
SPTM | State Street® SPDR® Portfolio S&P 1500 Composite Stock Market ETF | 0.030% |
VOO | Vanguard S&P 500 ETF | 0.030% |
SCHX | Schwab U.S. Large-Cap ETF™ | 0.030% |
Source: Morningstar. Data is current as of July 1, 2026, and is intended for informational purposes only, not for trading purposes. | ||
» Ready to get started? See our roundup of the best online brokers for ETF investing
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How to choose a low-cost fund
When choosing a low-cost fund that works for your portfolio, you'll first want to decide between index funds and ETFs. (Read our full breakdown of the differences between index funds and ETFs.)
If you're starting with a small budget and don't want to stress about an investment minimum, or if you want more control over the taxes generated by your investment, ETFs may be a good fit.
But we're not knocking index funds. You may notice that many of the index funds on our list have lower expense ratios than the ETFs. A low (or nonexistent) expense ratio is a valid reason to choose a fund, so long as it otherwise meets your investment needs.
Another nice thing about index funds? Once you've met the investment minimum, if there is one, many brokers allow subsequent investments in any dollar amount you choose. ETFs, on the other hand, are traded in shares, and sometimes a single share can cost hundreds of dollars. However, these days, many brokers offer fractional shares, which (as the name implies) let you buy part of an ETF for a specific dollar amount instead of having to buy a full share.
The other — perhaps most important — thing you'll want to consider when choosing a low-cost fund is how it fits in with the rest of your portfolio. You don't want to weigh your investment choice too heavily on a fund's expense ratio. While it is an important aspect to consider, it's not the only one. Thinking about how a new investment fits with your existing holdings is key to ensuring you aren't overexposed to any one company or industry.
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