Should I Buy VOO or VTI?
VOO is the S&P 500; VTI is the entire U.S. market. Same Vanguard, same 0.03% fee, and their returns track within a fraction of a percent. Here's the real difference.
Don't have time? Here's what you need to know:
- 1VOO holds ~500 S&P 500 large-caps; VTI holds ~3,700 U.S. stocks of all sizes — both at a 0.03% fee.
- 2They overlap roughly 80% by weight, so their long-run returns track within a fraction of a percent.
- 3VTI offers slightly broader diversification; VOO offers the cleaner, more recognized S&P 500 benchmark.
- 4Own one as your U.S. core, not both, and pair it with an international fund for global coverage.
The Short Answer: You Can't Really Go Wrong
VOO tracks the S&P 500 — roughly 500 of the largest U.S. companies. VTI tracks the entire U.S. stock market — about 3,700 companies, adding mid-cap, small-cap, and micro-cap names on top of those same large-caps. Both are Vanguard funds charging an identical 0.03% expense ratio, and because large companies dominate both portfolios, their returns have historically tracked within a fraction of a percent per year.
If you own one, owning the other would barely change your results. The honest answer to "VOO or VTI" is that either is an excellent single-fund core for a U.S. equity allocation. The choice is about a small tilt toward smaller companies, not a fork in the road.
What Each Fund Actually Holds
VOO's index, the S&P 500, is a curated list of large U.S. companies selected by a committee, weighted by market capitalization. The biggest names — the major technology and consumer giants — sit at the top and drive most of the movement. It covers roughly 80% of the total U.S. stock market by value.
VTI holds essentially everything publicly traded in the U.S. that meets basic listing criteria. The top of VTI looks almost identical to VOO because both are capitalization-weighted, so the largest 500 stocks make up the vast majority of VTI too. The extra ~3,200 holdings are smaller companies that collectively account for roughly 15-20% of VTI's weight — enough to matter at the margins, not enough to dominate.
| VOO | VTI | |
|---|---|---|
| Index | S&P 500 | CRSP US Total Market |
| Holdings | ~500 large-caps | ~3,700 all-cap |
| Expense ratio | 0.03% | 0.03% |
| Market coverage | ~80% of U.S. value | ~100% of U.S. market |
| Mid/small-cap exposure | Minimal | Yes (~15-20% weight) |
| Issuer | Vanguard | Vanguard |
Does the Small-Cap Difference Matter?
In theory, small and mid-cap stocks have historically earned a modest return premium over large-caps and behave a little differently, so VTI is slightly more diversified. In practice, because both funds are market-cap-weighted, that extra exposure is diluted to a thin slice and rarely changes annual returns by more than a few tenths of a percent in either direction.
Over multi-decade periods the two have produced very similar total returns, sometimes VOO ahead, sometimes VTI, depending on whether large-caps or smaller companies led that stretch. Neither is reliably the winner. If you specifically want broader diversification across the whole U.S. market in one ticker, VTI edges it. If you want the cleaner, more famous large-cap benchmark, VOO edges it.
Tip: Don't own both VOO and VTI together — they overlap roughly 80%, so holding both just adds a redundant ticker without meaningfully improving diversification.
Which Should You Choose?
Pick VTI if you want "the whole U.S. market" in a single fund and like the idea of automatically owning tomorrow's large-caps while they're still small. Pick VOO if you prefer the S&P 500 specifically, want it to pair cleanly with a 401(k) that already offers S&P 500 funds, or simply like the benchmark you hear quoted every day.
A common, sensible setup is one of these as your U.S. core, paired with an international fund such as VXUS for global coverage. That combination — total or near-total U.S. plus international — is the backbone of most low-cost portfolios. The ETF return calculator can show how either fund might compound on your own contribution schedule; the inputs that move the needle are your savings rate and time horizon, not the choice between these two.
Frequently Asked Questions
Is VOO or VTI better for long-term investing?
Both are excellent long-term core holdings with an identical 0.03% fee. VTI is marginally more diversified because it adds mid- and small-cap stocks, while VOO sticks to the 500 largest companies. Over long periods their returns track within a fraction of a percent, so neither is clearly better — choose based on whether you want total-market coverage (VTI) or the S&P 500 specifically (VOO).
Do VOO and VTI overlap?
Heavily. Because both are weighted by market capitalization, the same large companies dominate both funds, giving them roughly 80% overlap by weight. VTI simply adds thousands of smaller companies on top. That's why owning both at once is redundant — you'd just be duplicating your large-cap exposure.
Can I switch from VOO to VTI or vice versa?
Inside a tax-advantaged account like an IRA or 401(k), switching is free and tax-neutral, so move to whichever you prefer. In a taxable account, selling appreciated shares triggers capital-gains tax that usually outweighs any benefit of switching between two nearly identical funds — it's generally better to just direct new contributions to your preferred one.
Should I own both VOO and VTI?
There's little reason to. They share about 80% of the same holdings, so combining them doesn't meaningfully improve diversification — it just clutters your account with two overlapping positions. Pick one as your U.S. core and add a separate international fund if you want broader diversification.
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Alex Harrington
CFA Level II Candidate, Finance & Economics
Alex Harrington is an independent ETF researcher and personal finance writer with over 8 years of experience analyzing exchange-traded funds. A CFA Level II candidate with a background in economics, Alex has reviewed 800+ ETFs and helped thousands of beginners build their first investment portfolios through clear, jargon-free education.
This content is for educational purposes only and does not constitute financial advice. Past performance does not guarantee future results. Consult a licensed financial advisor before making investment decisions.