VO vs VOO: Which ETF Is Better in 2026?
A metric-by-metric comparison of Vanguard Mid-Cap Index Fund ETF Shares (VO) and Vanguard S&P 500 ETF (VOO) — both US Mid Cap / US Large Cap Blend funds — using ETFValuer's daily-updated rankings.
Educational content — not financial advice. Data as of July 25, 2026. ~5 minute read.
The Verdict
VO (US Mid Cap) and VOO (US Large Cap Blend) sit in different corners of the market, so this is less a head-to-head than a question of what role each would play. They can be complements rather than alternatives — the metrics below show how differently the two have actually behaved.
On ETFValuer's overall model — which blends return, risk-adjusted performance, cost, drawdown, size and volatility — VOO scores higher: 76.0 (Grade B+) versus 66.3 for VO. That doesn't make VO a bad fund; it means VOO currently edges it out on this specific mix of factors. Read the metric-by-metric breakdown below before deciding which matters more for your own portfolio.
Head-to-Head: Every Metric
| VO | VOO | |
|---|---|---|
| Category | US Mid Cap | US Large Cap Blend |
| Expense ratio | 0.03% | 0.03% |
| Fund size (AUM) | $224.0B | $1.67T |
| Dividend yield | 3.73% | 0.80% |
| 1-year return | +13.56% | +17.89% |
| 3-year return | +48.17% | +67.91% |
| Volatility | 12.60% | 12.62% |
| Max drawdown | -19.02% | -18.69% |
| Sharpe ratio | 0.68 | 1.02 |
| ETFValuer score | 66.3 | 76.0 |
| Grade | B | B+ |
| Overall rank | #158 | #39 |
Bold marks the better value in each row. "Better" is directional only (e.g. lower cost, higher return) — it isn't a recommendation by itself. See the full methodology.
Cost
On cost, the two are essentially tied — VO charges 0.03% a year versus VOO's 0.03%. A difference this small (about $0.00 a year on a $10,000 position) isn't a reason to choose one fund over the other.
What VO's Fees Cost You
VO charges an expense ratio of 0.03% a year, deducted automatically from the fund's value. Small percentages compound into real money — adjust the figures below to see the impact on your own numbers.
Assumes a constant gross return and no additional contributions — a simplification, but it isolates exactly what the expense ratio costs. Try the full fee calculator to model contributions and compare any two funds.
Performance & Risk
Over the trailing 3 years, VOO returned +67.91% versus +48.17% for VO — a gap of about 19.7 percentage points. On risk, VOO has held up better historically, with a shallower max drawdown (-18.69% vs. -19.02%). VOO currently has the better risk-adjusted return (Sharpe ratio of 1.02 vs. 0.68), meaning it delivered more return per unit of volatility taken on.
How Closely Do They Track Each Other?
Over the last 3.0 years of daily returns (752 shared trading days), VO and VOO show a strong correlation of 0.889 — clearly related, with room to diverge. There is some genuine differentiation here, but not enough to call these complementary holdings. Pairing them mostly concentrates risk rather than spreading it.
| Measure | Value | What it means |
|---|---|---|
| Daily return correlation | 0.889 | Strong — clearly related, with room to diverge |
| R-squared | 79.1% | 79.1% of VO's daily moves are explained by VOO's |
| Tracking error (annualised) | 6.98% | Typical yearly spread between the two funds' returns |
| Annualised return over 3.0y | VO +14.03% · VOO +19.14% | VOO ahead by 5.10 points a year |
Correlation alone understates how far these can drift. Across every rolling 12-month window in the period, VO finished as much as +5.5 points ahead of VOO at the best extreme and -13.1 points at the worst — a 18.6-point spread between the best and worst year of relative performance. Two funds can correlate tightly day to day and still deliver very different outcomes over any single year you happen to hold them.
Calculated from daily total returns over the trailing 3-year window, recomputed every day this site refreshes. Correlation of 1.00 means the two funds moved in lockstep; 0.00 means their daily moves were unrelated.
Holdings Overlap
VO and VOO share no companies among their top 10 reported holdings. That points to genuinely different exposure, so holding both is more likely to diversify than to duplicate. Full portfolios may still overlap further down the list.
Based on the top 10 holdings in each fund's most recent SEC N-PORT-P filing.
Which One Should You Pick?
Lean VO if…
- Current income matters to you — it yields 3.73% against 0.80%
Lean VOO if…
- You care about return per unit of risk — its Sharpe ratio of 1.02 beats 0.68
- You weight recent results heavily — it returned 67.9% over 3 years against 48.2%
- You want the deeper, more liquid market ($1671B in assets vs $224B) and the tighter spread (0.065% vs 0.497%)
These two are not really substitutes, so "both, in some proportion" is often the right answer rather than picking one. Model the blend with the Portfolio Blender.
Frequently Asked Questions
Is VO or VOO better?
On ETFValuer's overall model — which blends return, risk-adjusted performance, cost, drawdown, size and volatility — VOO scores higher: 76.0 (Grade B+) versus 66.3 for VO. That doesn't make VO a bad fund; it means VOO currently edges it out on this specific mix of factors. Read the metric-by-metric breakdown below before deciding which matters more for your own portfolio.
Which has the lower expense ratio, VO or VOO?
VOO currently has the lower expense ratio (0.03% vs. 0.03%).
Can I hold both VO and VOO?
You can, though the benefit is limited. At a correlation of 0.89, VO and VOO fall together far more often than not, so owning both adds complexity and a second expense ratio without much real diversification. Most investors are better served picking one.
Go deeper on either fund
Full daily-updated metrics, holdings context, and category peers.