Introduction
The CSI 300 Index and SSE Composite Index are two pivotal stock market benchmarks in China's financial ecosystem. While both track market performance, their construction methodologies differ significantly—from component selection to calculation formulas. This guide breaks down these differences across seven critical dimensions.
Core Differences at a Glance
1. Base Date & Reference Points
CSI 300:
- Base Date: December 31, 2004
- Base Point: 1,000 points
- Calculation: Uses adjusted market cap of 300 constituent stocks
SSE Composite:
- Base Date: December 19, 1990
- Base Point: 100 points
2. Constituent Count
| Index | Number of Constituents |
|---|---|
| CSI 300 | 300 A-shares |
| SSE Composite | All listed stocks (A/B-shares) |
Selection Criteria: Quality vs. Completeness
CSI 300’s Rigorous Filters
Eligibility:
- Minimum 3-month listing (exceptions for top 30 market cap stocks)
- Excludes ST/*ST and suspended stocks
- No major compliance issues or financial irregularities
Selection Process:
- Rank stocks by 1-year average daily turnover + market cap
- Eliminate bottom 50% by turnover
- Top 300 by market cap become components
👉 Discover how index components impact portfolio strategies
SSE Composite’s Inclusive Approach
- Covers all SSE-listed stocks (A/B-shares)
- No selective screening
Calculation Formulas: Adjusted vs. Raw Capitalization
CSI 300’s Methodology
Index = (Current-day Adjusted Market Cap / Base-day Market Cap) × 1,000
Adjusted Market Cap = ∑(Price × Adjusted Shares) Key Adjustments:
- Free-float shares
- Tiered share buffers
SSE Composite’s Simpler Model
Index = (Current-day Total Market Cap / Base-day Market Cap) × 100
Market Cap = ∑(Price × Total Shares Outstanding) Maintenance Rules: When Changes Happen
CSI 300 Adjustments
- Semi-annual Reviews: Max 10% component rotation
- Special Events: Mergers, delistings, or major corporate actions trigger ad-hoc changes
- Divisor Updates: Adjusts for corporate actions (e.g., dividends, splits)
SSE Composite Updates
- New Listings: Added on 11th trading day
- Divisor Method: Continuity-focused adjustments for share changes
Top 10 Holdings Contrast (2010 Snapshot)
| CSI 300 | Weight (%) | SSE Composite | Weight (%) |
|---|---|---|---|
| China Merchants Bank | 3.22 | PetroChina | 12.47 |
| Bank of Communications | 2.91 | ICBC | 7.17 |
| Minsheng Bank | 2.65 | Sinopec | 4.70 |
👉 See how index weightings influence market trends
FAQs: Quick Clarifications
Q1: Which index better represents large-cap stocks?
A: The CSI 300—it deliberately selects top market-cap stocks, whereas SSE Composite includes all sizes.
Q2: How often are components rebalanced?
A: CSI 300 reviews semi-annually; SSE Composite adds new listings automatically.
Q3: Why does SSE Composite have higher single-stock weights?
A: Its uncapped methodology allows mega-caps like PetroChina to dominate.
Key Takeaways
- CSI 300: Curated, free-float-adjusted, large-cap focused
- SSE Composite: Broad, unrestricted market snapshot
- Investor Tip: Use CSI 300 for blue-chip exposure, SSE Composite for whole-market beta
Both indices serve distinct purposes—your choice depends on investment objectives. Always cross-check current methodologies, as rules evolve over time.