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The International Sustainability and Carbon Certification body (ISCC) — the global standard for sustainable supply-chain certification — published on 15 February 2026 an update to ISCC PLUS v4.2. From 1 October 2026 it introduces significant restrictions on the mass balance method.
For the post-consumer recyclate industry this is a major change. The previous model — accounting “allocation” of recyclate to specific product batches without requiring physical segregation — was the basis for many brand commitments. Coca-Cola, Unilever, L’Oréal and Nestlé all anchor their rPET and bio-based targets on ISCC PLUS mass balance. The new rules do not invalidate those commitments, but they tighten the verification.
What mass balance means in ISCC PLUS
Mass balance is an accounting method: a facility receives e.g. 1 000 t of mixed rPET and virgin PET, 400 t of which is certified recyclate. The producer can manufacture 1 000 t of polymer and declare 400 t as “ISCC PLUS recyclate” even though every pellet is physically a blend. The balance must be maintained: you cannot sell more certified than entered.
Operationally convenient — reuses existing extrusion lines without splitting them. Marketing-wise convenient too — the brand can print “contains 30% rPET” on the bottle without physically separating the stream.
What v4.2 changes
1. Mandatory proof of physical segregation for critical batches
For food-contact packaging, mass balance is still permitted, but an auditable proof is required:
- Separate silos for certified and non-certified material with volume recording
- Separate batch IDs across all MRP/ERP documents
- Physical segregation at least at the finishing step (final extrusion before packaging)
The legacy practice of “balance at plant level” (mix everything, reconcile at month-end) no longer meets the standard for food-grade.
2. Full chain documentation — from collection to preform
ISCC now requires an unbroken documentation chain from the first PCR collection point to the final packaging producer. Every link must be ISCC PLUS certified and every transfer must generate a Sustainability Declaration with batch ID and mass. This rules out spot buys from non-certified intermediaries with later book-keeping into the balance.
3. Credit pool — new flexibility for technical grades
For non-food technical grades (rHDPE, rPP industrial regrind), ISCC introduced credit pooling — letting a producer balance across its entire European network rather than per facility. This lowers compliance cost for large corporations.
Market implications
Recyclers: rising operating costs (silos, traceability, double audit) but a rising premium for certified material. Wood Mackenzie estimates the ISCC PLUS premium over non-certified rPET will widen from 8% today to 14–16% by Q4 2026.
FMCG brands: the largest groups (Coca-Cola, Unilever, Danone, P&G) have renegotiated contracts requiring v4.2 compliance from 1 October 2026. Smaller regional brands may struggle to secure supply — certified rPET shortage is a real risk in Q4 2026.
Chemical recycling: the segment that benefited most from mass balance is now required to demonstrate real physical incorporation of recovered monomer into final polymer. End of pure accounting. Industry-wide investment to restructure production paths estimated at over EUR 1.8 bn by end-2027.
Practical recommendation for buyers
If you buy rPET in 2026 with an “ISCC PLUS mass balance” declaration:
- Check the certificate date. Certificates issued before 15 February 2026 stay valid under v4.1 until 30 September 2026. After that — v4.2 upgrade required.
- Demand batch IDs in the Sustainability Declaration. A declaration that only says “ISCC PLUS product” without batch identification does not meet v4.2.
- For food-grade packaging — prefer physical segregation. Mass balance is becoming a compliance risk in this category. Suppliers offering physical segregation are the safer strategic choice.
The next standard release (v5.0) is scheduled for Q2 2028 and may close mass balance for food-grade entirely. Those who invest in physical-segregation infrastructure today will have the market advantage in 2028.