When market participants discuss "small-cap index," they almost always refer to the “Russell 2000," a broad, well-known index widely used by fund managers and investors alike.
However, there's another small-cap index that quietly outperforms, filters out unprofitable companies, and offers better diversification: the S&P 600.
While the S&P 500 is generally recognized as the definitive benchmark for large-cap stocks, the S&P 600 is still awaiting its recognition. Here's why it deserves serious consideration in your portfolio.
The Profitability Filter
The S&P 600 launched in 1994 with stricter entry criteria than the Russell 2000. To qualify, a company must:
Market cap between $1.2 billion and $8 billion.
Maintain 10% public float.
Show positive earnings in the most recent quarter AND the past four consecutive quarters combined.
That last requirement matters. A lot.
The profitability screen filters out speculative, cash-burning companies that dominate the Russell 2000. Here's the difference:
Russell 2000: ~44% of companies are unprofitable.
S&P 600: ~20% unprofitable in Q3 2025.
Profitable companies tend to outperform over time. This reflects in the returns.
A $10000 investment would have grown at 9.86% CAGR in the S&P 600 vs 9.71% CAGR in the Russell 2000
Tech Diversification
The S&P 600 offers the best diversification if you have heavily invested in the tech stocks, as it offers strong exposure to the "real economy" such as industrials, financials, and consumer discretionary sectors that move differently from Silicon Valley giants.
For instance, 35% of the S&P 500 is made up of the Information Technology sector, while the diversification is much wider in the S&P 600, as a sector % doesn’t exceed more than 18%. You're not making a concentrated bet on any one industry.
Sector concentration comparison:
Sector | S&P 500 | S&P 600 |
|---|---|---|
Information Technology | 35% | 14% |
Financials | 13% | 17% |
Industrials | 8% | 17% |
Consumer Discretionary | 10% | 14% |
S&P 600 Sector Distribution
If tech corrects—and it will eventually—the S&P 600 provides a cushion through exposure to companies that make physical goods, provide regional banking services, and operate in cyclical industries tied to economic activity.
Performance
3 Year Rolling Return between Russell 2000 and S&P 600
The S&P 600 doesn't always beat the Russell 2000. Over the last 119 rolling three-year periods, it outperformed 52% of the time. Basically, a coin flip.
But here's where it gets interesting: the S&P 600 shines in down markets.
During declining periods, it outperformed the Russell 2000 61% of the time with an average active return of +0.13%.
Translation: When markets get rough, the profitability filter matters. Unprofitable companies get crushed. Profitable companies hold up better.
Risk and Return Metrics
Here's the complete risk and return breakdown comparing the two indices (via their ETFs: IWM for Russell 2000, IJR for S&P 600):
Metric | iShares Russell 2000 ETF (IWM) | iShares Core S&P Small-Cap ETF (IJR / S&P 600) |
|---|---|---|
Arithmetic Mean (Annualized) | 12.09% | 12.25% |
Geometric Mean (Annualized) | 9.71% | 9.86% |
Standard Deviation (Annualized) | 20.80% | 20.80% |
Downside Deviation (Monthly) | 3.92% | 3.89% |
Maximum Drawdown | -32.29% | -36.12% |
Beta | 1.19 | 1.16 |
Alpha (Annualized) | -6.45% | -5.87% |
Sharpe Ratio | 0.45 | 0.45 (tie) |
Sortino Ratio | 0.67 | 0.68 |
Treynor Ratio (%) | 7.83 | 8.15 |
Calmar Ratio | 0.60 | 0.38 |
Information Ratio | -0.48 | -0.44 |
Upside Capture (%) | 101.35 | 98.73 |
Downside Capture (%) | 130.38 | 125.62 |
Historical VaR (5%) | 8.91% | 8.50% |
Conditional VaR (5%) | 12.25% | 12.22% |
Positive Months | 63.87% | 63.03% |
The Case for S&P 600 in Your Portfolio
If you want small-cap exposure but hate volatility: The S&P 600's profitability screen reduces blow-up risk from cash-burning companies.
If you're overweight tech: The S&P 600 gives you diversification into industrials, financials, and consumer discretionary—sectors that behave differently from mega-cap growth.
If you care about risk-adjusted returns: The S&P 600 wins on Sortino and Treynor ratios, meaning better returns per unit of downside risk.
If you expect a recession or correction: The S&P 600 historically outperforms the Russell 2000 in down markets (61% of declining periods).
The Russell 2000 Still Has a Role
The Russell 2000 isn't bad. It's a broader, more inclusive index. For fund managers benchmarking performance, it's the standard.
But for investors building portfolios? The S&P 600 makes a stronger case:
Higher quality companies (profitability filter).
Better downside protection (lower downside capture).
True sector diversification (no single sector >18%).
Slightly better long-term returns (9.86% vs. 9.71%).
The Bottom Line
The Russell 2000 gets all the attention. The S&P 600 quietly does the work.
If you're allocating to small caps, ask yourself: do you want breadth or quality? Do you want every small company, including the 44% that are unprofitable? Or do you want companies that actually make money?
The S&P 600 isn't perfect—it gives up some upside in melt-up markets and had a worse max drawdown. But for investors prioritizing risk-adjusted returns, downside protection, and diversification away from tech, it's the better choice.
The S&P 600 deserves recognition as more than just "the other small-cap index." It's a differentiated strategy with a profitability screen that matters—especially when markets turn.
Important disclosures: This newsletter is provided for informational purposes only and does not constitute investment advice. All investments involve risk, including possible loss of principal. Please consult with your financial advisor before making investment decisions.
