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✅ Fact-Checked by the FinanceLiveHub Editorial Team
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📖 15 min read
Best Index Funds to Invest In (2025)
If you have been putting off investing because it feels complicated or expensive, index funds are the answer most financial experts quietly rely on. Warren Buffett has publicly recommended them for decades. Nobel Prize-winning economists have built careers proving why they consistently beat actively managed funds. And yet, millions of people still do not know which ones to actually buy.
This guide cuts through the noise. You will find the best index funds available in 2025, broken down by category, cost, and who they are best suited for. Whether you are starting with $100 or $100,000, there is a fund here for you.
⚡ Key Takeaways
- The best index funds in 2025 charge as little as 0.015% per year in fees.
- FXAIX, VTSAX, and SWPPX are the top-rated S&P 500 and total market funds.
- Over 15 years, more than 85% of actively managed funds underperform their index (SPIVA Scorecard).
- A simple two or three-fund portfolio beats most complex strategies for everyday investors.
- The single most important factor is starting early and contributing consistently.
What Is an Index Fund and Why Should You Care?
An index fund is a type of investment that tracks a market index, such as the S&P 500 or the total U.S. stock market. Instead of a fund manager picking individual stocks, the fund automatically holds every stock in the index it follows.
This matters for three core reasons:
- Lower costs: No active management means expense ratios often below 0.05% per year.
- Consistent performance: Over 90% of actively managed funds underperform their benchmark index over a 15-year period.
- Instant diversification: One S&P 500 index fund gives you exposure to 500 of the largest U.S. companies at once.
The concept is simple. The results, when applied consistently over time, are powerful.
How We Selected the Best Index Funds for 2025
The FinanceLiveHub editorial team evaluated each fund on:
- Expense ratio (lower is better)
- Assets under management (indicates trust and liquidity)
- 5-year and 10-year annualized returns
- Minimum investment requirement
- Index tracked and diversification level
- Availability across major brokerages
All funds listed are available at major U.S. brokerages including Fidelity, Vanguard, Schwab, and most online platforms.
Best S&P 500 Index Funds in 2025
The S&P 500 is the most widely tracked index in the world, representing approximately 80% of total U.S. stock market value.
1. Fidelity 500 Index Fund (FXAIX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.015% |
| Minimum Investment | $0 |
| 10-Year Annualized Return (approx.) | ~12.9% |
| Assets Under Management | $500+ billion |
| Best For | Fidelity account holders, beginners |
FXAIX is one of the best performing S&P 500 index funds in existence. Its expense ratio of just 0.015% means you pay $1.50 per year for every $10,000 invested. There is no minimum investment, making it accessible to anyone. If you have a Fidelity account, this should likely be your first stop.
2. Vanguard 500 Index Fund Admiral Shares (VFIAX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.04% |
| Minimum Investment | $3,000 |
| 10-Year Annualized Return (approx.) | ~12.8% |
| Assets Under Management | $900+ billion (including ETF share class) |
| Best For | Long-term investors with $3,000+ to start |
Vanguard essentially invented the low-cost index fund, and VFIAX remains one of the gold standards. The $3,000 minimum is a barrier for some, but for those who can meet it, the fund is rock-solid. Vanguard also offers the ETF version (VOO) with no minimum if you prefer the exchange-traded format.
3. Schwab S&P 500 Index Fund (SWPPX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.02% |
| Minimum Investment | $0 |
| 10-Year Annualized Return (approx.) | ~12.8% |
| Assets Under Management | $90+ billion |
| Best For | Schwab account holders |
SWPPX is Schwab’s flagship index fund and competes directly with FXAIX on cost. No minimum investment and a near-zero expense ratio make it ideal for new investors using a Schwab brokerage or retirement account.
Best Total Stock Market Index Funds
Total market funds go beyond the S&P 500 and include mid-cap and small-cap stocks, giving you broader exposure to the entire U.S. economy.
4. Fidelity Total Market Index Fund (FSKAX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.015% |
| Minimum Investment | $0 |
| Number of Holdings | 3,800+ |
| Best For | Investors wanting full U.S. market exposure |
FSKAX holds over 3,800 U.S. stocks and tracks the Dow Jones U.S. Total Stock Market Index. It gives you ownership of small companies that may not yet qualify for the S&P 500.
5. Vanguard Total Stock Market Index Fund (VTSAX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.04% |
| Minimum Investment | $3,000 |
| Number of Holdings | 3,900+ |
| Best For | Buy-and-hold investors who want everything |
VTSAX is one of the most recommended funds in the FIRE (Financial Independence, Retire Early) community. If you want to own a slice of virtually every publicly traded U.S. company, VTSAX does that in a single fund. The ETF equivalent is VTI, which trades with no minimum.
Best International Index Funds
6. Fidelity International Index Fund (FSPSX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.035% |
| Minimum Investment | $0 |
| Countries Covered | Developed markets (Europe, Japan, Australia, etc.) |
| Best For | Adding international developed market exposure |
FSPSX tracks the MSCI EAFE Index and covers large and mid-cap stocks in 21 developed countries outside the U.S. and Canada. It is a low-cost way to add geographic diversification to a U.S.-heavy portfolio.
7. Vanguard Total International Stock Index Fund (VTIAX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.11% |
| Minimum Investment | $3,000 |
| Countries Covered | Both developed and emerging markets |
| Best For | Investors who want global coverage beyond the U.S. |
VTIAX covers both developed and emerging markets — Japan, the U.K., China, India, and Brazil in one fund. Combined with VTSAX or VFIAX, it forms the backbone of a globally diversified two-fund portfolio.
Best Bond Index Funds for Stability
8. Vanguard Total Bond Market Index Fund (VBTLX)
| Detail | Info |
|---|---|
| Expense Ratio | 0.05% |
| Minimum Investment | $3,000 |
| What It Tracks | Bloomberg U.S. Aggregate Float Adjusted Index |
| Best For | Risk reduction, retirees, conservative investors |
VBTLX holds over 10,000 U.S. bonds including government, corporate, and mortgage-backed securities. It is the most popular bond fund in the U.S. and anchors millions of retirement portfolios.
Index Fund vs ETF: What Is the Difference?
| Feature | Index Fund (Mutual Fund) | ETF |
|---|---|---|
| How You Buy | End of day price | Trades like a stock all day |
| Minimum Investment | Often $1,000 to $3,000 | $1 with fractional shares |
| Automatic Investing | Easy to automate | Usually manual |
| Tax Efficiency | Slightly less efficient | Generally more tax efficient |
| Best For | Retirement accounts (IRA, 401k) | Taxable brokerage accounts |
How to Build a Simple Index Fund Portfolio
Buy one total market fund like FSKAX or VTSAX and contribute monthly. The simplest approach — ideal for most investors under 40.
Pair a U.S. total market fund with an international fund. Example: 80% VTSAX + 20% VTIAX. Domestic and global exposure at ultra-low cost.
Add bonds for stability near retirement. Common allocation for your 30s: 60% VTSAX + 30% VTIAX + 10% VBTLX. Shift bond percentage higher as you age.
What Is an Expense Ratio and Why It Matters More Than You Think
The expense ratio is the annual fee automatically deducted from your returns. It compounds against you significantly over decades. Here is a real example with $10,000 invested at 10% per year for 30 years:
| Expense Ratio | Final Value After 30 Years | Lost to Fees |
|---|---|---|
| 0.015% (FXAIX) | ~$172,800 | ~$400 |
| 0.50% (avg. active fund) | ~$160,000 | ~$13,000 |
| 1.00% (high-fee fund) | ~$147,600 | ~$25,600 |
The difference between a 0.015% fund and a 1% fund is more than $25,000 on a single $10,000 investment over 30 years. This is why cost is one of the most important factors when choosing an index fund.
Pros and Cons of Investing in Index Funds
Pros
- Extremely low fees — often under 0.05% per year
- Instant diversification across hundreds of stocks
- Historically outperform 85%+ of active funds over 15 years
- Completely passive — no research or stock picking needed
- Zero minimum at Fidelity and Schwab
Cons
- You match the market — never beat it
- No protection against broad market downturns
- Vanguard mutual funds require $3,000 minimum
- International funds slightly more expensive
Common Mistakes to Avoid
1. Trying to Time the Market
Time in the market consistently beats timing the market. Every year spent waiting for the “right moment” costs you compounding returns you can never recover.
2. Checking Your Portfolio Daily
Short-term volatility is normal. Daily balance-checking leads to emotional decisions that hurt long-term returns. Quarterly reviews are more than enough.
3. Owning Too Many Funds
15 index funds do not mean more diversification. One or two funds cover everything. More funds usually just create overlapping holdings with no added benefit.
4. Ignoring Tax Location
Where you hold matters. Keep bond funds in tax-advantaged accounts (Roth IRA, 401k). Growth-focused stock funds work better in taxable brokerage accounts.
5. Stopping Contributions During Downturns
Market drops are buying opportunities. Dollar-cost averaging during dips lowers your average cost per share. Stopping contributions during a downturn is the single most damaging thing most investors do.
Frequently Asked Questions
Final Verdict: Which Index Fund Should You Start With?
| Your Situation | Recommended Fund |
|---|---|
| Beginner with less than $3,000 | FXAIX or FSKAX (Fidelity, no minimum) |
| Beginner at Schwab | SWPPX (no minimum) |
| Long-term investor with $3,000+ | VTSAX or VFIAX (Vanguard) |
| Want global diversification | VTSAX + VTIAX two-fund combo |
| Near retirement or conservative | Add VBTLX for bond exposure |
| Prefer ETFs with no minimum | VOO, VTI, or SCHB |
Final Thoughts
The most important step is simply to start. Picking the “perfect” fund matters far less than starting early and staying consistent. A $0-minimum fund with a 0.015% expense ratio held for 30 years will almost certainly outperform a perfectly timed investment made years from now.
Open a brokerage account, set up an automatic monthly contribution, and let compound interest do the work. That is the core of index fund investing — and it is one of the most proven wealth-building strategies available to everyday investors in 2025.
FinanceLiveHub Editorial Team
Personal Finance & Investing Researchers
The FinanceLiveHub editorial team researches and fact-checks every guide before publishing. Our investing content is reviewed against publicly available fund data from Fidelity, Vanguard, Schwab, and the SPIVA Scorecard. We do not accept sponsored placements for editorial rankings.
