Guide · US Small Cap
Best small-cap ETFs
A small-cap fund concentrates exposure on the smaller end of the US equity market. Small-caps have historically delivered a modest long-run return premium over large-caps in exchange for higher volatility and (academically documented) more illiquid trading. Whether the premium will persist is contested; what isn't contested is that a total-market fund already holds small-caps at their market weight, so a dedicated small-cap fund is a deliberate overweight, not a coverage gap.
How the scoring ranks these funds
Cost separates the field cleanly. VB, VBR, and IJR run at 3-6 bps and dominate the top of the leaderboard; IWM (the Russell 2000 fund every news anchor quotes) costs 19 bps for similar exposure. AVUV is the small-cap-value fund Boglehead factor-tilt investors specifically reach for — it costs more (25 bps) but applies a quality + value screen on top of the size cut.
See the methodology for the full formula behind each sub-score.
Top picks
-
95
composite / 100
Vanguard's broad small-cap fund. 3 bps and the highest-scoring catalog fund in the category. Tracks the CRSP US Small Cap Index — broad market-cap-weighted small-cap, no factor screening.
- Expense
- 0.030%
- AUM
- $177.42B
- Issuer
- Vanguard
- Detail
- VB page →
-
94
composite / 100
Vanguard's small-cap value fund. 5 bps; CRSP small-cap-value index. The middle ground for investors who want a value tilt on top of small-cap without paying the AVUV premium.
- Expense
- 0.050%
- AUM
- $64.90B
- Issuer
- Vanguard
- Detail
- VBR page →
-
94
composite / 100
iShares' S&P SmallCap 600 fund. 6 bps; tracks the S&P 600, which screens for profitable small-cap names — modestly higher quality tilt than the Russell 2000. Works as a tax-loss-harvesting partner to VB.
- Expense
- 0.060%
- AUM
- $102.56B
- Issuer
- iShares
- Detail
- IJR page →
-
88
composite / 100
iShares' Russell 2000 fund. 19 bps — the most-traded small-cap ETF on the market but six times the cost of VB for similar exposure. The natural fund for short-term traders (deep options market) but not the preferred long-term holding.
- Expense
- 0.19%
- AUM
- $76.88B
- Issuer
- iShares
- Detail
- IWM page →
-
85
composite / 100
Avantis US Small Cap Value ETF. 25 bps; applies a value + profitability screen on top of a small-cap universe. The most-cited factor-tilt fund on Boglehead forums; meaningfully different exposure from the index-tracking small-cap options above.
- Expense
- 0.25%
- AUM
- $26.16B
- Issuer
- Avantis
- Detail
- AVUV page →
Also in the category
Other funds scoring in this category. Same data, no editorial commentary yet.
Small-cap vs total market
A US total-market fund (VTI) holds small-caps at about 6-8% of the fund by market cap. Adding a small-cap sleeve overweights that — a common Boglehead-style tilt is to hold 80% total-market plus 20% small-cap value, which roughly doubles the small-cap exposure of the overall portfolio. The size premium is real but episodic; allocations to small-cap value should be sized to a level you can hold through multi-year periods of underperformance vs. large-cap.
Russell 2000 vs S&P SmallCap 600
These are the two largest small-cap indexes, and they hold different stocks. The Russell 2000 includes any company in the smaller half of the Russell 3000 universe, with no profitability requirement. The S&P SmallCap 600 includes a profitability screen — companies must have positive trailing earnings to be added. The S&P 600 has historically delivered slightly higher returns at similar risk; the difference is small enough to be in the "interesting trivia" bucket for most investors.
Guide. Picks come from the live PlainIndex composite for this category; editorial commentary on each pick is hand-written. Re-pulled with every catalog refresh.
PlainIndex publishes data and editorial commentary — nothing here is personalized investment advice. Read the methodology for how the scores referenced here are computed.