Assessment Methodology
SNSUC-LI v1.0 · effective 2026-11-01 — every rule on this page maps to the published assessments and is independently auditable.
01Scope & Positioning
SNSUC-LI (SNSUC Listing Index) is an offer-side assessment of bulk petrochemical products computed from live listings on this platform. It answers one question: where is the asking-price center for each category on SNSUC right now?
It is
- A point-in-time snapshot of live asking prices (offer-side)
- A mechanical statistic under published rules, free of editorial adjustment
- A transparent index traceable to individual listing records
It is not
- Not a transaction-based assessment; it does not represent deal levels
- Not a contractual pricing basis; not to be referenced in contract price clauses
- Not investment advice or a price forecast of any kind
Roadmap: as real trade execution data accumulates on the platform, future versions will introduce transaction-based assessments under a separate version number and effective date, without retroactively amending this version.
02Data Sources & Tiers
All platform data is classified into two tiers and labeled accordingly. SNSUC-LI assessments use L1 data only.
| Tier | Content | Used in assessments |
|---|---|---|
| L1 | Proprietary: live listings (category / price / origin / quantity / trade terms / publish time) | Yes · sole source |
| L2 | Referenced: market quotes (sources labeled in Data Center), JODI / EIA public statistics | No · context only |
03Sample Rules (five filters)
- Online — Only listings with isOnline ≠ false enter the universe.
- Availability — Only status = available; reserved and finished listings are excluded.
- Price validity — Numeric price > 0.
- Currency/unit consistency — Only CNY per metric ton; other bases are excluded to avoid conversion noise.
- Sanctions-origin denial — Iran-origin listings are automatically denied from the index and trigger an internal compliance review, consistent with the platform’s sanctions-screening red line.
04Calculation
fence = [ Q1 − 1.5 × IQR , Q3 + 1.5 × IQR ]
assessment = median( prices within fence ) , n ≥ 3
- Outlier removal: within each category, prices outside the IQR fence are dropped and the dropped count is published alongside the assessment.
- Assessment: the median of in-fence samples is the assessment value; mean, low–high range and sample size are published with it.
- Publication threshold: categories with fewer than 3 in-fence samples are withheld for that issue.
- History: daily assessments are archived (capped at 120 points per category) for trend display and period-over-period change.
05Publication, Corrections & Governance
- Publication: assessments are recalculated and republished with the platform data pipeline; every issue carries a generatedAt timestamp (Beijing time).
- Corrections: any market participant may challenge an assessment; we respond in writing within 72 hours. Verified calculation errors are corrected with original records retained. Contact: info@snsuc.com
- Versioning: any methodological change is released under a new version number with an effective date; prior versions are archived and published history is never retroactively amended.
06Appendix · Current Assessment Specifications
| Category | Unit | n | Assessment | Range |
|---|---|---|---|---|
| Crude Oil | CNY/吨 | 5 | 4,650 | 4,600 ~ 4,650 |
| Synthetic Rubber | CNY/吨 | 4 | 17,095 | 16,880 ~ 17,370 |
| Base Oil | CNY/吨 | 4 | 7,945 | 7,830 ~ 8,030 |
| Natural Rubber | CNY/吨 | 4 | 19,385 | 19,300 ~ 19,690 |
| Industrial White Oil | CNY/吨 | 4 | 8,265 | 8,210 ~ 8,360 |
| Bitumen | CNY/吨 | 4 | 5,390 | 5,310 ~ 5,440 |
| Lubricants | CNY/吨 | 4 | 9,145 | 9,090 ~ 9,330 |
| Lubricating Grease | CNY/吨 | 4 | 12,545 | 12,510 ~ 12,650 |
| Liquid Paraffin | CNY/吨 | 4 | 8,150 | 7,970 ~ 8,190 |
| Carbon Black | CNY/吨 | 4 | 8,885 | 8,780 ~ 9,030 |
| Fuel Oil | CNY/吨 | 3 | 5,680 | 5,680 ~ 5,720 |
| Petroleum Coke | CNY/吨 | 3 | 2,380 | 2,380 ~ 2,380 |
| Paraffin Wax | CNY/吨 | 3 | 8,010 | 7,940 ~ 8,050 |
07Change Log
| Version | Effective | Change |
|---|---|---|
| v1.0 | 2026-11-01 | Initial release: offer-side assessments for 13 categories, IQR-fence + median. |
