VTI vs VOO: Total Stock Market vs S&P 500 - Which Is Better?

Compare VTI (Total Stock Market) vs VOO (S&P 500). Understand the 4,000+ stock difference, small cap exposure, historical performance, and which provides better diversification.

#VTI #VOO #Total Market #S&P 500 #Small Cap #Index Investing #Diversification

The Great Debate

This is one of the most common questions in index investing: Should I buy VTI (Total Stock Market) or VOO (S&P 500)?

Both are Vanguard funds. Both are incredibly cheap. Both will give you broad U.S. stock exposure. And for the past several decades, they've performed almost identically.

So does it matter? Let's dig in.

Quick Comparison

Feature VTI (Total Market) VOO (S&P 500)
Index Tracked CRSP US Total Market S&P 500
Number of Stocks ~4,000 ~500
Market Cap Coverage ~100% of US market ~80% of US market
Expense Ratio 0.03% 0.03%
AUM ~$400 Billion ~$480 Billion
Dividend Yield ~1.4% ~1.4%
Includes Small Caps Yes No
Includes Mid Caps Yes Limited

What is the Total Market?

VTI tracks the CRSP US Total Market Index, which includes virtually every publicly traded U.S. company - about 4,000 stocks in total.

This includes:

  • Large caps: Apple, Microsoft, Amazon, etc. (same as S&P 500)
  • Mid caps: Companies worth $2-10 billion
  • Small caps: Companies worth $300M-2B
  • Micro caps: Tiny companies worth under $300M

VTI Breakdown by Market Cap

Category % of VTI Approx. # of Stocks Also in VOO?
Large Cap ~72% ~500 Yes (this IS the S&P 500)
Mid Cap ~18% ~400 Partially
Small Cap ~8% ~1,500 No
Micro Cap ~2% ~1,600 No

Here's the key insight: About 80% of VTI is the same large-cap stocks that dominate VOO. The "extra" 3,500 stocks only make up about 20% of the total fund value.

Key Differences Explained

Holdings Count: 4,000 vs 500

VTI holds about 8x more stocks than VOO. But this is misleading because of market-cap weighting.

In both funds, the top 10 holdings are identical and make up about 30% of the fund:

Rank Company VTI Weight VOO Weight
1 Apple 6.2% 7.0%
2 Microsoft 5.8% 6.5%
3 NVIDIA 4.5% 5.1%
4 Amazon 3.4% 3.8%
5 Alphabet (GOOGL) 2.0% 2.2%
6 Alphabet (GOOG) 1.7% 1.9%
7 Meta 1.9% 2.1%
8 Berkshire Hathaway 1.6% 1.8%
9 Tesla 1.4% 1.6%
10 UnitedHealth 1.2% 1.3%

The weights are slightly lower in VTI because the small/mid caps dilute the large caps. But functionally, both funds rise and fall with the same mega-cap tech stocks.

Market Cap Coverage

VOO covers about 80% of the total U.S. market by value. VTI covers essentially 100%.

That extra 20% comes from:

  • Mid-cap companies not in the S&P 500
  • Small-cap companies (like those in the Russell 2000)
  • Micro-cap stocks too small for most indexes

Historical Performance

This is where it gets interesting. Despite holding 8x more stocks, VTI and VOO have performed almost identically.

Returns Comparison (Annualized)

Period VTI Return VOO Return Difference
1 Year (2025) 25.1% 25.3% -0.2%
3 Years 9.8% 10.1% -0.3%
5 Years 14.2% 14.5% -0.3%
10 Years 12.4% 12.6% -0.2%
15 Years 13.8% 14.0% -0.2%

VOO has slightly outperformed VTI over most recent periods. Why? Large-cap growth stocks (especially tech) have dominated. The small caps in VTI have been a slight drag on performance.

Year-by-Year Variation

Year VTI VOO Small Caps Helped?
2025 25.1% 25.3% No
2024 24.8% 25.0% No
2023 26.1% 26.3% No
2022 -19.5% -18.1% No (hurt)
2021 25.7% 28.7% No
2020 21.0% 18.4% Yes!
2016 12.7% 11.8% Yes!

Small caps occasionally outperform (like 2020 and 2016), but large caps have dominated the past decade. This is cyclical and will likely change in the future.

The Small Cap Question

The main argument for VTI over VOO is small-cap exposure. But is this actually valuable?

The Case FOR Small Caps

  • Historical premium: Small caps have outperformed large caps over very long periods (100+ years)
  • Academic research: The "size factor" is one of the Fama-French factors that explain returns
  • Diversification: Small caps don't move in perfect lockstep with large caps
  • Future winners: Today's mega-caps were yesterday's small caps

The Case AGAINST Small Caps

  • Recent underperformance: Small caps have lagged for 10+ years
  • Higher volatility: Small caps are more volatile with similar recent returns
  • Lower quality: Many small caps are unprofitable or poorly managed
  • Less analyst coverage: More potential for fraud and accounting issues
  • Tiny allocation anyway: Only 10% of VTI is true small/micro cap

Small Cap Premium: Dead or Just Sleeping?

Period Small Cap vs Large Cap (Annual) Verdict
1926-2024 +1.8% Small caps won
2000-2024 +0.5% Roughly even
2010-2024 -2.5% Large caps won
2020-2024 -4.0% Large caps dominated

The small-cap premium has been absent or negative for over a decade. Some argue it's been "arbitraged away" now that everyone knows about it. Others say it's cyclical and will return. Nobody knows for sure.

Diversification Deep Dive

VTI holds more stocks, but does that mean better diversification?

Correlation Between VTI and VOO

The correlation between VTI and VOO is approximately 0.99. That's nearly perfect correlation. For practical purposes, they move together almost identically.

This makes sense when you remember that 80% of VTI is literally the same stocks as VOO.

Sector Allocation Comparison

Sector VTI Weight VOO Weight Difference
Technology 30.5% 31.5% -1.0%
Healthcare 12.5% 12.0% +0.5%
Financials 13.0% 12.5% +0.5%
Consumer Discretionary 10.5% 10.5% 0%
Industrials 9.0% 8.5% +0.5%
Communication 8.5% 9.0% -0.5%
Other Sectors 16.0% 16.0% 0%

The sector weights are nearly identical. VTI has slightly less tech and slightly more industrials/financials (sectors with more small caps), but the differences are marginal.

True Diversification

If you want meaningfully different diversification, you need to look beyond VTI vs VOO:

  • International stocks: VXUS adds exposure to 8,000+ non-US companies
  • Bonds: BND provides truly different risk/return characteristics
  • Real estate: VNQ offers sector diversification
  • Small-cap value: VBR or AVUV for concentrated small-cap exposure

Which Is Better for You?

Choose VTI If:

  • You want to own "the whole market" for philosophical reasons
  • You believe small caps will eventually outperform again
  • You want one fund to cover all U.S. stocks
  • Simplicity appeals to you (one fund = entire market)
  • You're building a three-fund portfolio (VTI + VXUS + BND)

Choose VOO If:

  • You're fine owning just the 500 largest companies
  • You prefer the most liquid, most tracked index
  • You want to add small-cap exposure separately (VB, VBR)
  • You're skeptical of the small-cap premium
  • Your 401(k) offers an S&P 500 fund but not total market

Decision Framework

Situation Better Choice Reason
Simple one-fund U.S. equity VTI Complete market coverage
401(k) with limited options VOO/S&P 500 fund Usually the only index offered
Want to tilt small-cap VOO + VB More control over allocation
Matching spouse's 401(k) Either Match whatever they have
Tax-loss harvesting partner VTI ↔ ITOT Can swap without wash sale

The "Core and Explore" Approach

Some investors use VOO as their core holding and add specific tilts:

  • 80% VOO - Core large-cap exposure
  • 10% VB or VBR - Small-cap tilt (if you want it)
  • 10% VUG or VTV - Growth or value tilt

This gives more control than VTI's fixed allocation. But it also requires more management.

The Bottom Line

Here's the honest truth: it doesn't matter much.

Key Takeaways

  • Correlation is 0.99: VTI and VOO move almost identically
  • Same expense ratio: 0.03% for both - essentially free
  • Similar returns: Historically within 0.2-0.3% of each other annually
  • Small caps matter... marginally: Only 10% of VTI is true small/micro cap
  • Neither is wrong: Both are excellent choices for U.S. equity exposure

My Personal Take

I use VTI in my taxable accounts because:

  1. I like owning "everything" for psychological comfort
  2. It's one fewer decision to make
  3. Small caps might outperform eventually (or might not)

But my 401(k) only offers an S&P 500 fund, and I don't lose sleep over it. The difference is tiny.

What Actually Matters

Instead of agonizing over VTI vs VOO, focus on things that matter more:

  • Savings rate: How much are you investing?
  • Asset allocation: How much in stocks vs bonds?
  • International diversification: Do you own non-US stocks?
  • Time in market: Are you staying invested through volatility?
  • Avoiding mistakes: Not panic selling in crashes

The difference between VTI and VOO is a rounding error compared to these factors.

The 50-Year Test

Imagine it's 2075 and you're looking back at your investing career. Will you care whether you picked VTI or VOO?

No. You'll care that you invested consistently, stayed the course during bear markets, and let compounding work. The VTI vs VOO debate will seem absurdly trivial.

So pick one, buy it, and move on with your life. Either choice is excellent.


This is not investment advice. Past performance does not guarantee future results. Consider your personal situation before investing.

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Disclaimer: This article is for informational purposes only and does not constitute investment advice or a recommendation to buy or sell any financial instruments. All investment decisions must be made at your own responsibility. Forex and cryptocurrency trading carries risk of capital loss.