VOO vs VTI: Which Vanguard ETF Should You Own?

The Most Common Index Fund Question

If you spend any time in investing communities, this question comes up constantly: VOO or VTI? Both are from Vanguard, both are dirt cheap, both are core portfolio holdings for millions of investors. And yet people agonize over the choice.

Here's the short answer: for most investors, it doesn't matter much. But the long answer is worth understanding, because the differences do exist and they do matter in specific situations.

What Each Fund Actually Holds

VOO tracks the S&P 500 Index, which covers roughly 500 of the largest US companies by market cap. Think Apple, Microsoft, Amazon, Nvidia, and Berkshire Hathaway. These are the giants. The S&P 500 represents about 80% of the total US stock market by market capitalization. VTI tracks the CRSP US Total Market Index, which holds approximately 3,600 to 4,000 stocks. It includes everything in the S&P 500, plus mid-cap and small-cap stocks. Those smaller companies make up the remaining 20% of the US market.

So VTI is a superset. If you own VTI, you already own everything in VOO, plus a few thousand more companies.

The Numbers That Matter

Both funds charge an expense ratio of 0.03% per year. That's $3 per year on a $10,000 investment. On cost, they're identical.

AUM is substantial for both: VOO sits at roughly $550 billion, VTI around $400 billion. Both are among the largest ETFs on the planet. Liquidity is never a concern with either.

Performance is where things get interesting -- and anticlimactic. Over the past decade, VOO and VTI have performed nearly identically. The difference has typically been less than 0.1% annually in either direction. Some years VTI wins slightly because small caps outperform. Other years VOO wins slightly because large caps dominate. Over a long horizon, the gap is small enough that it rarely changes outcomes in any meaningful way.

Top Holdings Overlap

The top holdings in VTI are essentially the same as VOO -- because those mega-cap stocks dominate by weight. The additional 3,000+ stocks in VTI make up only about 20% of the fund's total value. Apple and Microsoft alone account for roughly 12-14% of each fund.

This is why the performance is so similar. Adding thousands of smaller companies only slightly changes the overall picture when the big ones dominate.

When VTI Wins

If you believe small and mid-cap stocks will outperform large caps over your investment horizon, VTI gives you that exposure without any additional cost. Historically, small caps have shown higher long-run returns, though with more volatility.

If you're a one-fund investor who wants the broadest possible US market exposure, VTI is the cleaner answer. You own everything.

If you're building a portfolio that might include a separate small-cap tilt (like a VIOO or VBR allocation), VOO is the better large-cap core since VTI would create overlap.

When VOO Wins

If you're comparing returns head-to-head with a benchmark, VOO tracks the S&P 500 directly. Most people quote market returns using the S&P 500, so VOO makes benchmarking clean.

If you're combining with an international fund and want to approximate the global market-cap weights, S&P 500 plus VXUS (international) is a common and clean pairing.

The Practical Reality

Both funds are excellent. Both are the right answer for most long-term investors. The choice often comes down to:

• Are you at Fidelity (where FSKAX might be more convenient for total market)? VOO/VTI both work but check your brokerage's own index offerings.
• Do you have an existing holding in one or the other? Stay in it. Switching has no meaningful benefit.
• Starting fresh? Coin flip. Seriously.

The only wrong answer is spending months paralyzed by this decision instead of investing.

Compare Them Yourself

Want to see the actual historical performance difference? Compare VOO and VTI side by side, including expense-adjusted returns over 1, 3, and 5 year periods.

Compare VOO vs VTI on StockResearch

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This post is for informational purposes only and does not constitute financial advice. Past performance does not guarantee future results. Always do your own research before investing.