# Russell 2500 Index: What It Is and How It Differs from the Russell 2000

Published: 2026-01-31
Author: Warren Team
URL: https://www.heywarren.com/blog/russell-2500-index

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The Russell 2500 Index is a US equity index maintained by FTSE Russell that tracks the performance of the 2,500 smallest companies in the Russell 3000 Index — covering small-cap and mid-cap stocks collectively known as "SMID cap." It is calculated as the intersection of the Russell 2000 (small caps) and the Russell Midcap Index (mid caps), offering a broad representation of the US SMID market. For investors, the Russell 2500 provides exposure to a wider segment of smaller US companies than the popular Russell 2000 while avoiding the mega-cap and large-cap dominance of the S&P 500. Understanding what the Russell 2500 covers, how it is constructed, and how it compares to the Russell 2000 and S&P 500 is important for institutional allocators, index fund investors, and anyone analysing SMID-cap equity performance.

## What Is the Russell 3000 Family?

The Russell 2500 is part of the FTSE Russell family of US equity indices:

![The Russell 2500 sits within the broader FTSE Russell family, covering the bottom 2,500 stocks of the Russell 3000.](data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20600%20211%22%20width%3D%22600%22%20height%3D%22211%22%20role%3D%22img%22%3E%3Ctitle%3EHierarchy%3C%2Ftitle%3E%3Crect%20width%3D%22100%25%22%20height%3D%22100%25%22%20fill%3D%22%23f8fafc%22%2F%3E%3Crect%20x%3D%22220%22%20y%3D%2220%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22%232563eb%22%2F%3E%3Ctext%20x%3D%22300%22%20y%3D%2254%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22700%22%20fill%3D%22white%22%3ERussell%203000%3C%2Ftext%3E%3Cpath%20d%3D%22M%20300%2078%20L%20300%20105.5%20L%20120%20105.5%20L%20120%20133%22%20stroke%3D%22%23cbd5e1%22%20stroke-width%3D%222%22%20fill%3D%22none%22%2F%3E%3Crect%20x%3D%2240%22%20y%3D%22133%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22white%22%20stroke%3D%22%230891b2%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22120%22%20y%3D%22158%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2213%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ERussell%201000%3C%2Ftext%3E%3Ctext%20x%3D%22120%22%20y%3D%22176%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2210%22%20fill%3D%22%2364748b%22%3ETop%201%2C000%20%28large%20cap%29%3C%2Ftext%3E%3Cpath%20d%3D%22M%20300%2078%20L%20300%20105.5%20L%20300%20105.5%20L%20300%20133%22%20stroke%3D%22%23cbd5e1%22%20stroke-width%3D%222%22%20fill%3D%22none%22%2F%3E%3Crect%20x%3D%22220%22%20y%3D%22133%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22white%22%20stroke%3D%22%230891b2%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22300%22%20y%3D%22158%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2213%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ERussell%202500%3C%2Ftext%3E%3Ctext%20x%3D%22300%22%20y%3D%22176%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2210%22%20fill%3D%22%2364748b%22%3EBottom%202%2C500%20%28SMID%20cap%29%3C%2Ftext%3E%3Cpath%20d%3D%22M%20300%2078%20L%20300%20105.5%20L%20480%20105.5%20L%20480%20133%22%20stroke%3D%22%23cbd5e1%22%20stroke-width%3D%222%22%20fill%3D%22none%22%2F%3E%3Crect%20x%3D%22400%22%20y%3D%22133%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22white%22%20stroke%3D%22%230891b2%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22480%22%20y%3D%22158%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2213%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ERussell%202000%3C%2Ftext%3E%3Ctext%20x%3D%22480%22%20y%3D%22176%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2210%22%20fill%3D%22%2364748b%22%3EBottom%202%2C000%20%28small%20cap%29%3C%2Ftext%3E%3C%2Fsvg%3E)

*The Russell 2500 sits within the broader FTSE Russell family, covering the bottom 2,500 stocks of the Russell 3000.*

| Index | Coverage | Companies | Cap Range |
|---|---|---|---|
| Russell 3000 | Broadest US market | 3,000 | All public US equities |
| Russell 1000 | Large cap | Top 1,000 of Russell 3000 | >~$5B |
| Russell 2000 | Small cap | Bottom 2,000 of Russell 3000 | ~$250M–$5B |
| Russell Midcap | Mid cap | Bottom 800 of Russell 1000 | ~$2B–$30B |
| **Russell 2500** | **SMID cap** | **Bottom 2,500 of Russell 3000** | **~$250M–$10B** |

The Russell 2500 = Russell 2000 + the bottom 500 stocks of the Russell 1000 (mid-cap). It captures both small-cap and mid-cap in a single benchmark.

## Russell 2500 vs. Russell 2000 vs. S&P 500

| Feature | Russell 2500 | Russell 2000 | S&P 500 |
|---|---|---|---|
| Number of stocks | ~2,500 | ~2,000 | 500 |
| Cap range | SMID (~$250M–$10B) | Small (~$250M–$5B) | Large (>$15B) |
| Largest company weight | ~0.3%–0.5% | ~0.5%–0.7% | ~7% (top 5 dominate) |
| Mid-cap exposure | Yes (bottom 500 of Russell 1000) | No | Some |
| Diversification | Very high | High | Mega-cap concentrated |
| Domestic revenue exposure | Very high (>80%) | Very high (>85%) | Moderate (50%–60%) |
| Volatility | Higher than S&P 500 | Higher than Russell 2500 | Lower |
| Typical beta vs. S&P 500 | ~1.2x–1.3x | ~1.3x–1.5x | 1.0x |

![The Russell 2500 carries lower market beta than the Russell 2000, reflecting its additional mid-cap holdings.](data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20800%20210%22%20width%3D%22800%22%20height%3D%22210%22%20role%3D%22img%22%3E%3Ctitle%3EComparison%3C%2Ftitle%3E%3Crect%20width%3D%22100%25%22%20height%3D%22100%25%22%20fill%3D%22%23f8fafc%22%2F%3E%3Ctext%20x%3D%22230%22%20y%3D%2257.5%22%20text-anchor%3D%22end%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ERussell%202500%3C%2Ftext%3E%3Crect%20x%3D%22240%22%20y%3D%2225%22%20width%3D%22401.78571428571433%22%20height%3D%2255%22%20rx%3D%226%22%20fill%3D%22%232563eb%22%2F%3E%3Ctext%20x%3D%22653.7857142857143%22%20y%3D%2257.5%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22700%22%20fill%3D%22%232563eb%22%3Ex1.25%3C%2Ftext%3E%3Ctext%20x%3D%22230%22%20y%3D%22152.5%22%20text-anchor%3D%22end%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ERussell%202000%3C%2Ftext%3E%3Crect%20x%3D%22240%22%20y%3D%22120%22%20width%3D%22450%22%20height%3D%2255%22%20rx%3D%226%22%20fill%3D%22%237c3aed%22%2F%3E%3Ctext%20x%3D%22702%22%20y%3D%22152.5%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22700%22%20fill%3D%22%237c3aed%22%3Ex1.4%3C%2Ftext%3E%3C%2Fsvg%3E)

*The Russell 2500 carries lower market beta than the Russell 2000, reflecting its additional mid-cap holdings.*

The key difference between the Russell 2500 and Russell 2000: the Russell 2500 includes 500 additional mid-cap stocks that tend to be more liquid, more profitable, and less volatile than pure small-caps. This makes the Russell 2500 a smoother representation of smaller US companies with slightly lower volatility.

## Russell 2500 Reconstitution

Like all Russell indices, the Russell 2500 is reconstituted annually, typically in late June. FTSE Russell ranks all US public equity by market capitalisation and reconstructs the index boundaries:

- Companies that have grown into large-cap territory are moved to the Russell 1000
- Companies that have declined or gone public are added to or dropped from the index
- The reconstitution causes significant trading activity as passive funds tracking the index buy newly added stocks and sell deleted ones

**Index arbitrage around reconstitution**: Stocks added to the Russell 2000/2500 often experience price appreciation in the weeks before the effective date as index-tracking funds are forced to buy them. This creates a well-documented but increasingly arbitraged seasonal pattern.

## Why Investors Use the Russell 2500

**SMID-cap exposure**: Institutional investors seeking exposure to the "sweet spot" between small and large cap — where many growing companies trade before they become large caps — use the Russell 2500 as a benchmark.

**Lower concentration risk**: Compared to the S&P 500, where the top 10 stocks can represent 30%+, the Russell 2500 is highly diversified — the top holding typically represents less than 0.5% of the index.

**US economic exposure**: Small and mid-cap companies derive most of their revenue domestically. The Russell 2500 is therefore a purer play on the US economy than multinational-heavy large-cap indices.

**Active vs. passive debate**: Smaller-cap markets are considered less efficient (less analyst coverage, less institutional ownership), creating more opportunities for active managers to outperform passive indices — the Russell 2500 is a popular benchmark for SMID-cap active managers.

## Historical Performance

Small and mid-cap stocks (Russell 2500) have historically outperformed large-cap stocks over long periods — this is known as the **size premium** in factor investing. However:
- The size premium has been inconsistent in recent decades
- 2010–2023 saw significant large-cap outperformance driven by mega-cap tech (Apple, Microsoft, Amazon, Alphabet, Nvidia)
- SMID-cap stocks typically outperform during economic recoveries and underperform during risk-off periods

**Benchmark funds**: Several ETFs track the Russell 2500, including the SPDR S&P 600 Small Cap fund and various SMID-cap active mutual funds use it as their primary benchmark.

## Authoritative Sources

For deeper background and primary-source data on this topic, the following authoritative sources are useful starting points:

- [IRS](https://www.irs.gov/)
- [SEC](https://www.sec.gov/)

## Conclusion

The Russell 2500 Index provides comprehensive coverage of US SMID-cap equities — the 2,500 smallest companies in the Russell 3000, combining the Russell 2000 small-cap universe with the bottom 500 mid-cap stocks. It offers broader and slightly less volatile small/mid-cap exposure than the Russell 2000, high domestic US revenue exposure, and extensive diversification. Institutional investors use it as a benchmark for SMID-cap active and passive strategies. For related equity market and index concepts, see our guides on [outstanding stocks definition](/blog/outstanding-stocks-definition) and [efficiency frontier](/blog/efficiency-frontier).

Warren at [heywarren.com](https://heywarren.com) helps equity investors, portfolio managers, and analysts understand index construction, SMID-cap market dynamics, and benchmark selection for US equity strategies.

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## Related Reading

**More from Warren**:
- [Shares Outstanding: What They Are and How to Calculate Market Cap](/blog/outstanding-stocks-definition)
- [Efficient Frontier: What It Is and How Portfolio Optimisation Works](/blog/efficiency-frontier)
- [Return on Equity: What It Is and How to Calculate ROE](/blog/return-on-equity)

**Authoritative sources**:
- [FTSE Russell — Russell 2500 Fact Sheet](https://www.ftserussell.com/products/indices/russell-us)
- [SEC — Index Fund Regulation](https://www.sec.gov/investor/alerts/indexfundsandetfs.pdf)
- [CFA Institute — Equity Index Investing](https://www.cfainstitute.org/en/membership/professional-development/refresher-readings/introduction-industry-company-analysis)