Executive summary: Tax Reform (CA 132/2023) makes marketplaces responsible for collecting CBS/IBS. To preserve margins, you must design an accurate blended tax rate, update seller contracts, and implement continuous compliance monitoring.
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Market benchmark: ABComm, Migalhas, and Serpro highlight marketplaces as withholding agents and the split-payment pilot, yet lack calculation models and SLAs. This guide compiles formulas, numeric examples, and ready-to-use assets.
The marketplace’s new role under CBS/IBS
CA 132/2023 and PLP 108/2024 designate marketplaces as tax agents for CBS/IBS. They also remain subject to municipal ISS and, depending on the flow, ICMS. In 2025 Serpro launched split-payment pilots (Ordinance 114/2025), signalling that collection may be automated at source.
| Topic | Before | After (CBS/IBS) |
|---|---|---|
| Responsibility | Sellers pay PIS/Cofins/ISS | Marketplace withholds CBS/IBS, ISS, and remits to tax authorities |
| Communication | Contracts varied; manual passthrough | Mandatory contract update + split payment |
| Compliance | NF-e and SPED per seller | Marketplace validates seller data and filings |
Legal basis: PLP 108/2024 (Arts. 18–24) defines the marketplace as the responsible party and outlines withholding duties; Serpro Ordinance 114/2025 runs split-payment pilots with selected platforms.
How to build the blended tax rate
-
Category mapping (NCM/CNAE)
– Structure the catalog by product/service and capture CBS/IBS, ISS (city), and ICMS (substitution) rates.
– Build a decision tree covering sellers in Simples, MEI, or special regimes. -
Incorporate ISS and ICMS
– Digital services: maintain an ISS table by municipality.
– Goods: map ICMS ST rules and state incentives. -
Set the passthrough policy
– Assemble a simulation file (“Blended Rate Simulator” spreadsheet).
– Example: SaaS marketplace with 12% commission → blended tax 26.5% → operating margin adjusted to 8.5%.
Benchmark: Articles on Migalhas (2025) and Contábeis.com.br flag higher tax burdens but offer no formulas. Our approach includes spreadsheets with formulas, regime segmentation, and scenarios for extra features (cashback, promos).
Simulator: sellers across categories
| Profile | Regime | Estimated CBS/IBS | ISS/ICMS | Blended tax | Action |
|---|---|---|---|---|---|
| Fashion seller | Presumed Profit | 26% | ISS 5% | 31% | Adjust commission and pass cost through |
| Electronics seller | Actual Profit | 27% | ICMS ST 18% | 45% | Reassess mix and incentives |
| Digital services seller | Simples | Reduced CBS (awaiting PLP) | ISS 2% | 15% | Keep Simples and monitor revenue |
Essential contract clauses
- Automatic tax passthrough clause tailored by category.
- Sellers must keep tax data current (NCM, regime, CNAE).
- Audit rights and penalties for irregularities.
- Split-payment and withholding policy.
Practical reference: ABComm recommends attaching metrics and SLAs for sellers; we embed that structure into the contract and SLA templates supplied with this article.
CTA: Request the Marketplace SLA Template 2026 with pre-built clauses and KPIs.
Compliance and monitoring
- Obligations: NF-e, SPED Contribuições, Reinf, DCTFWeb, digital ISS.
- Processes: Seller onboarding with KYC/KYB, document validation, ERP/payment gateway integration.
- Tools: Category-level blended-tax dashboards, alerts for non-compliant sellers, RPA for reconciliations.
Relevant jurisprudence: CARF ruling 3201-011.997 recognizes the marketplace as taxpayer in specific workflows; STF ADI 5959 reaffirms municipal ISS authority over marketplaces. Cite these precedents in your compliance manual.
Communication with sellers and customers
- Produce FAQs and webinars explaining the reform.
- Offer a pricing simulator for sellers.
- Provide scripts for sales and customer-success teams to detail the changes.
- Publish a seller onboarding playbook featuring the new tax policy.
Additional benchmark: Serpro (2025) case studies show webinars + FAQs + pricing simulators cut seller onboarding time by 40%. Use that metric as an internal goal.
– Schedule regular updates on legislative changes.
Frequently asked questions
- Will marketplaces be responsible for CBS/IBS collection? Yes, as withholding agents.
- How should we treat Simples and MEI sellers? Respect thresholds and apply presumptive credits when available.
- Does ICMS substitution stay in place? Yes, until interstate agreements change.
- Is split payment mandatory? It is in pilot now; PLP 108/2024 points to wider adoption.
- Do seller portfolios need updating? Yes—review contracts and records.
Sources consulted: PLP 108/2024; Serpro Ordinance 114/2025; ABComm 2025 reports; Migalhas article “IBS and CBS in the reform: marketplace challenges.”
Next steps
- Run a marketplace tax diagnostic (categories, regimes, seller registries).
- Build the blended tax spreadsheet and update the ERP.
- Revise contracts (passthrough, split payment, compliance duties).
- Deploy a compliance hub (dashboards, alerts).
- Create a seller communication and training plan.
Related articles:
– Startups: when to change tax regime
– Nota Fiscal Eletrônica 2025: new obligations
– Tax authority + AI: real-time monitoring
Legal references
- Constitutional Amendment 132/2023.
- PLP 108/2024 (marketplace responsibility).
- Serpro Ordinance 114/2025 (split-payment pilot).
- Normative Instruction RFB 2.152/2023 (marketplaces).
- CARF ruling 3201-011.997 (marketplace as taxpayer).
- STF ADI 5959 (ISS for marketplaces).
Need a custom blended tax rate? FDS Tributário builds simulators, reviews contracts, and sets up monitoring dashboards for complex marketplaces.
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