How Fastmarkets arrives at an antimony price (and other minor-metal prices)

Step	What Fastmarkets’ reporters do
1. Define the reference product up-front	Each price has a fixed code and a tight specification (purity, lot size, incoterm, payment terms, publication window). For antimony one of the main references is MB-SB-0002 Antimony MMTA standard grade II, in-warehouse Rotterdam, $/t — 99.65 % Sb min, 10 t lots, cash terms, published Wed & Fri 14-15 h London.
2. Open a “time window” for data	Only deals, firm bids/offers and other verifiable market indications concluded since the previous assessment are eligible. The length of that window (daily, weekly, etc.) is set so that there are always enough datapoints.
3. Gather primary evidence	Reporters phone, message or e-mail a balanced panel of producers, traders, consumers and brokers. Transaction data are preferred, but firm bids/offers and “market-heard” indications are also logged. Contributors may sign a Data Submitter Agreement; all data go into Fastmarkets’ secure MInD database.
4. Screen and normalise the data	Data that do not match the published spec (e.g. wrong purity, incoterm, payment terms) are adjusted or excluded. Reporters may also normalize minor differences (e.g. 30-day payment terms) so all datapoints are like-for-like. Outliers that cannot be corroborated are discarded.
5. Apply the data hierarchy	Concluded deals → verifiable bids/offers → other indications. The highest repeatable number becomes the high of the range; the lowest repeatable number becomes the low. Where liquidity allows, Fastmarkets may publish a single-point index (volume-weighted average); antimony is published as a low–high range because volumes are modest.
6. Editorial sense-check & publication	Two editors review the draft range, cross-check it against the raw evidence and wider market context, then release it at the scheduled time (for antimony, 14-15 h London). A short rationale note explaining the move accompanies each price; corrections or methodology changes are published as pricing notices and opened to market consultation.
7. Ongoing audit & methodology updates	Fastmarkets’ methodologies are IOSCO-aligned, reviewed at least annually and subject to external assurance. Any change (e.g. moving the China antimony assessment from weekly to monthly) goes through a public consultation.

Why this matters when you trade antimony

• Transparency on the exact material. Knowing the MB-SB-0002 spec lets you compare your Rotterdam offers with Fastmarkets’ quotation line-for-line.
• Clear timing. Because the window closes at 15 h London, deals done after that don’t affect that day’s range.
• Market-driven, but curated. The low-high range is built from real evidence, yet screened to stop distortion from one outlier deal.
• Auditable trail. If Fastmarkets corrects or changes a price, the notice and revised range are published so users can reconcile contracts or hedges.

In short, Fastmarkets for antimony (and other metals) is not a simple average of whatever numbers turn up on chat apps; it is a rules-based assessment that combines transaction data, strict specifications and editorial oversight to give the market a tradeable benchmark.