Catalytic Converter Unit Pricing vs. Assay: Which Settlement Method Fits Your Lot?

Catalytic Converter  |  2026-08-10 11:59:01   |   By Carolina Curiel

Catalytic converters can be sold by identified unit or settled through a processed-lot assay. This guide explains how each method works, what risks remain, and which questions should be answered before material changes hands.

Two common ways catalytic converters are purchased

Professional converter transactions generally follow one of two commercial models. The buyer may quote each converter by code or category, known as unit pricing. Alternatively, the material may be processed as a lot and paid according to a laboratory assay.

Both methods can be legitimate. The better fit depends on volume, converter mix, identification quality, cash-flow needs, buyer capabilities and the written settlement terms.

How unit pricing works

Under unit pricing, the buyer identifies each converter and assigns a price from a database, internal grade or negotiated category. The seller usually receives a quote before the converter is refined.

This method is common for repair shops, auto dismantlers and sellers with small or mixed quantities. It is fast and easy to audit when each unit is photographed and coded.

Advantages of unit pricing

• Faster quoting and payment.
• Clear unit-by-unit inventory.
• No need to wait for milling and laboratory analysis.
• Useful for identifiable OEM converters.
• Simple comparison between buyers when categories are equivalent.

Limitations of unit pricing

• A database match can be wrong when the code is incomplete or the unit is damaged.
• Different buyers may place the same converter in different grades.
• The seller does not receive direct measurement of contained PGMs.
• A buyer may discount for market volatility, recovery uncertainty and processing costs.

How assay settlement works

Under an assay model, converters are grouped into a controlled lot. The catalyst-bearing material is separated, milled, homogenized and sampled. A laboratory measures platinum, palladium and rhodium concentrations. The settlement then applies the agreed metal-price references, payable percentages and charges.

Published analytical research shows that XRF, ICP-based methods and fire-assay collection methods can be used to determine PGMs in prepared spent automotive catalyst samples. The analytical method matters, but representative sampling is equally critical.

Advantages of assay pricing

• Payment can be tied to measured PGM content.
• Mixed lots can be evaluated without identifying every unit individually.
• Large professional sellers can reconcile results across repeated lots.
• Written sampling and umpire procedures can support dispute resolution.

Limitations of assay pricing

• Processing and payment take longer.
• The seller must trust lot control, dust capture, homogenization and sampling.
• Fees and payable deductions can materially affect the result.
• Small lots may not justify separate processing, depending on the refiner.

The contained-metal calculation

The commercial payment is not necessarily equal to the gross value of contained metal. A settlement may apply payable percentages, refining charges, sampling charges, transport, treatment costs, penalties, price-adjustment periods and currency conversion.

Why sampling is the critical control point

A laboratory result can be precise and still be commercially wrong if the sample does not represent the full lot. Converter material is heterogeneous. A lot may contain different manufacturers, substrate types and PGM formulations.

Ask how the material is milled, blended and sampled. Confirm whether the seller receives a split sample and whether a sealed umpire sample is retained. The agreement should state how a disputed assay will be resolved.

Price date and metal reference

PGM markets can move between delivery and settlement. The contract should identify the platinum, palladium and rhodium price source, the currency, the pricing date or quotation period and any averaging method. Avoid vague language such as “market price at settlement” without a defined source.

Unit pricing and assay comparison

Questions to ask a unit-price buyer

1. Which database or category system is being used?
2. Will each converter be photographed and listed?
3. How are damaged or partial units adjusted?
4. When does the quoted price expire?
5. Are freight or handling deductions separate?

Questions to ask an assay buyer or refiner

1. Where will the lot be processed?
2. How will dust and fines be captured?
3. How will the lot be homogenized and sampled?
4. Which laboratory method will be used?
5. Will split and umpire samples be retained?
6. What are the payable percentages and all deductions?
7. Which PGM reference and pricing period apply?
8. When will the final settlement be issued?

Choosing the right method

Use unit pricing when rapid payment, traceable individual identification and simple administration are priorities. Consider assay settlement when the lot is large enough to justify controlled processing and the seller has confidence in the refiner’s sampling, analytical and settlement procedures.

The decision should be based on net payment and transparency, not a single headline percentage.

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