VTI vs VOO vs FSKAX.
Which index fund?
Compare total-market funds with S&P 500 funds side by side.
VTI, VOO, and FSKAX are effectively interchangeable. VTI = total U.S. market (~3,500 stocks), VOO = S&P 500 (~500 stocks), FSKAX = Fidelity total market. All charge 0.015–0.03%. The 10-year return difference between them is typically <0.6%/yr. Pick whichever your brokerage offers and stop deliberating.
- VTI (Vanguard): 0.03% ER, ~3,500 stocks, includes small- and mid-caps that VOO doesn't.
- VOO (Vanguard): 0.03% ER, ~500 stocks. The S&P 500 represents ~80% of U.S. market cap.
- FSKAX (Fidelity): 0.015% ER, ~3,700 stocks. Functionally identical to VTI but cheaper by 0.015%.
- Performance difference over 10 years: typically <0.6% per year. Small-cap tilt in VTI/FSKAX is marginal.
- The real decision is total market vs. S&P 500. For most people, the answer doesn't matter enough to agonize over.
This page covers US-listed funds. Outside the US? The logic is the same, the fund tickers and account names differ (ISAIndividual Savings Account (ISA)A UK tax-advantaged account where contributions are post-tax but all growth and withdrawals are tax-free.Full definition in the UK, TFSATax-Free Savings Account (TFSA)A Canadian tax-advantaged account where contributions are post-tax but all growth and withdrawals are tax-free.Full definition/RRSPRegistered Retirement Savings Plan (RRSP)A Canadian tax-deferred retirement account; contributions reduce taxable income and growth is tax-deferred until withdrawal.Full definition in Canada, Super in Australia, etc.).
This page picks between index-fund categories: total market vs S&P 500. For choosing among the three S&P 500 ETFs themselves, see VOO vs SPY vs IVV.
Total-market funds (VTI, FSKAX) and S&P 500 funds (VOO) have differed by less than 0.6% a year over most rolling 10-year periods, and all charge 0.015% to 0.03%. Use FSKAX at Fidelity or VTI elsewhere; what matters more is picking one, automating it and not delaying.
The comparison
| FUND | TYPE | ER | HOLDS | WHERE |
|---|---|---|---|---|
| VTI | Total US ETFExchange-Traded Fund (ETF)A basket of investments (stocks, bonds, or Bitcoin) that trades on a stock exchange like a single share. | 0.03% | ~3,500 | Anywhere |
| FSKAX | Total US Mutual | 0.015% | ~3,700 | Fidelity |
| VOO | S&P 500 ETF | 0.03% | 500 | Anywhere |
| FXAIX | S&P 500 Mutual | 0.015% | 500 | Fidelity |
| SPY | S&P 500 ETF | 0.0945% | 500 | Anywhere |
| VT | Total World ETF | 0.06% | ~9,800 | Anywhere |
Total market vs S&P 500: historically, the performance difference has been negligible, within 0.6%/year over most rolling 10-year periods. Either is fine.
SPY vs VOO: SPY charges 0.0945%, over 3x what VOO charges for the same index. No reason to buy SPY in a long-term portfolio.
The honest answer: FSKAX in a Fidelity account. VTI in a Vanguard or any brokerage account. The difference between all of these is negligible. Pick one and automate it. Do not let analysis paralysis delay investing by even one month.
Where to go from here
Last updated . Expense ratios per fund prospectuses. Disclosures · How pages are reviewed