JPK_MAG(2): Expanding reporting within the KSeF, JPK_VAT and JPK_CIT ecosystem

The changes are part of a broader trend towards the digitalisation of tax and accounting reporting and the alignment of JPK data with the requirements of the National e-Invoicing System (KSeF). 

The new structure should not be viewed solely as a technical update to the XML schema. In practice, it may require a review of inventory processes, the approach to maintaining subledger accounts for inventory transactions, the quality of source data, as well as the linkages between warehouse documents, KSeF e-invoices and accounting records. 

Why is this change important? 

The current JPK_MAG structure has primarily been tailored to reporting based on quantitative and value-based inventory records. JPK_MAG(2) expands this model by enabling reporting under additional methods of maintaining inventory subledgers as permitted under Polish accounting regulations. 

For taxpayers, this means a need to assess whether data available in warehouse and accounting systems is aligned with the scope and logic of the new structure. 

Importantly, if an entity operates multiple warehouses, a separate JPK_MAG file must be prepared for each warehouse. Consistency in naming (e.g. warehouse and product names) across files will also be critical. 

Key changes in JPK_MAG(2) 

• Introduction of the “Method” field - Taxpayers will be required to indicate the method used to maintain inventory subledger accounts (e.g. quantitative and value-based, quantitative-only, value-only, or expensing with periodic stock verification). 

• Variable data requirements - The mandatory scope of data fields (including quantity, unit of measure, unit price and value) will depend on the selected accounting method. 

• Integration with KSeF-The structure introduces fields to report e-invoice numbers (e.g. NrKSeFPZ, NrKSeFWZ), where warehouse documents are linked to invoices issued via KSeF. 

• New PW section -JPK_MAG(2) includes internal receipt documents (PW), broadening the reporting scope compared to the current structure. 

• Changes in warehouse document structure - The new format modifies the presentation of quantitative and value data and removes existing control sections for PZ, WZ, RW and MM documents. 

• New INW section -The structure will include inventory - taking data, including timing, responsible personnel and the method of conducting stocktakes. 

• Separation of inter-warehouse movements -The existing MM section is split into MMWE and MMWY, enabling clearer representation of inbound and outbound movements between warehouses. 

What does this mean in practice? 

JPK_MAG(2) significantly expands the scope of reportable data and covers a broader range of processes. In practice, this goes beyond XML adjustments and requires ensuring data completeness, quality and consistency, as well as the ability to reconcile warehouse data with accounting records and KSeF invoices. 

A key focus area will be establishing a controlled and consistent data flow from warehouse systems to the general ledger, ensuring a full audit trail and reconciliation capability. 

As reporting frameworks continue to evolve – including JPK_CIT – the need for alignment and control across JPK_MAG, KSeF, JPK_VAT and JPK_CIT becomes increasingly critical. Discrepancies across these areas may significantly complicate error analysis and audit processes. Early preparation is therefore recommended, particularly for organisations with complex system landscapes, multiple locations and advanced logistics operations. 

Recommended actions 

In preparation for JPK_MAG(2), we recommend in particular: 

• reviewing inventory accounting methods and their implementation in finance and warehouse systems; 

• verifying the availability and quality of data required by JPK_MAG(2), including quantities, values, units of measure and unit prices; 

• analysing linkages with KSeF for PZ and WZ documents, including the identification of e-invoice numbers; 

• reviewing processes related to internal receipts (PW) and inter-warehouse movements (MMWE and MMWY); 

• assessing inventory count processes with respect to data required in the INW section; 

• performing data mapping and test file generation to identify system, process or data quality gaps ahead of implementation; 

• ensuring consistency of reporting across JPK_MAG, KSeF, accounting records and supporting documentation. 

How PwC can help? 

The planned introduction of JPK_MAG(2) provides an opportunity to perform a broader review of data, processes and systems readiness for digital reporting. 

PwC supports organisations in preparing for new requirements by combining tax, accounting, process and technology expertise. 

We can support you with: 

• assessing the impact of JPK_MAG(2) on warehouse, accounting and tax processes; 

• analysing system readiness to generate compliant data; 

• identifying data and process gaps and developing remediation recommendations; 

• mapping data between source systems and the JPK_MAG(2) structure, including KSeF and other JPK reporting obligations; 

• supporting testing, validation and automation of reporting prior to go-live; 

• implementing solutions for generating JPK_MAG files. 

The period leading up to 1 January 2027 should be used to assess organisational readiness and improve the quality of warehouse data. This will help mitigate risks at the initial reporting stage and support further digitalisation of tax and accounting obligations. 

If you would like to discuss how JPK_MAG(2) may impact your organisation, please feel free to contact the PwC team.