STI 30 vs S&P 500 — 6-year backtest comparison
Side-by-side: the CS2 skin blue-chip index versus the canonical U.S. equity benchmark over the 2020-04 → 2026-04 window. Same start date, same end date, same methodology family (market-cap weighted, monthly snapshots, divisor adjustment for continuity). Different asset classes, different friction structures, dramatically different results.
The gap: ~117 percentage points over 6 years. Annualized, S&P 500 compounded at ~3x the rate of STI 30. And this is before adjusting for friction. After friction, the gap is wider.
Side-by-side comparison
| Metric | STI 30 | S&P 500 |
|---|---|---|
| Total return (2020-2026) | +37.5% | +154.4% |
| CAGR | ~5.5%/yr | ~16.6%/yr |
| Annualized volatility | ~30% | ~16% |
| Maximum drawdown | ~−40% | ~−25% |
| Sharpe vs CDI | −0.24 | +1.10 |
| Constituents | Top 30 CS2 skins by market cap (≥36mo history) | 500 large-cap U.S. equities |
| Rebalance cadence | Quarterly | Quarterly |
| Weighting | Market-cap (price × listings) | Market-cap (free-float) |
| Friction tax (replication) | ~15% Steam fee + days-to-weeks holding | ~0.09%/yr (SPDR SPY ETF expense ratio) |
| After-friction outperformance | Significant negative drag (each trade) | Negligible drag |
Why the 117pp gap?
The gap isn't about skin quality — it's structural. Three components:
1. Steam Market 15% fee
Every Steam Market sale loses 15% to fees, applied to gross proceeds, not gains. SPY has 0.09%/yr expense ratio. Over 6 years and meaningful trade frequency, the fee differential is enormous.
2. Holding-period drag
STI 30 includes blue-chip skins that occasionally exceed the $1,800 Steam Market cap. Selling those requires off-market execution, which can take days to weeks to clear. Capital locked in inventory can't earn the risk-free rate during the holding period.
3. Quarterly rebalance trade cost
Replicating STI 30 requires actually trading skins each quarter to match the new basket. Each trade pays the 15% fee. SPY does this internally with ETF in-kind creation/redemption mechanics that minimize tax and fee drag — a structural advantage of the equity ETF wrapper.
When does STI outperform S&P 500?
STI 30 (broad CS2 blue chips) has structurally underperformed S&P 500 over the documented window. But three sub-asset regimes within the CS2 skin market have outperformed:
- STI Cases (containers): +795% over 6 years vs S&P 500 +154%. Mechanism: Valve drop pool removal creates fixed/declining supply against growing CS2 player base.
- Contraband tier (M4A4 Howl alone): fixed supply since 2014, sustained appreciation regardless of macro environment.
- Pattern-rare subsets (Case Hardened blue gems, Doppler Sapphire/Black Pearl): structural pattern scarcity overrode the friction tax. See the most expensive pattern premiums for documented prices.
The exceptions all share one mechanism: supply-locked assets with growing demand. Where supply is flexible (mid-tier drops), the friction tax wins.
Period sensitivity
The 2020-2026 backtest sits inside a specific macro window: post-COVID equity rally, 2023-2024 AI bubble lifting S&P 500 to all-time highs. A different 6-year slice (the 2000-2006 post-dot-com flat decade, for example) would show different relative results. Read this comparison as one specific window, not a permanent ranking.
The structural drivers behind both indices remain in place — Valve drop policy continues to lock supply on legacy CS2 skins, and S&P 500 represents the U.S. corporate sector. The next 6 years could compress or widen the gap depending on macro regime, Valve policy, and CS2 engagement levels.