The New Face of Reporting: Anatomy of Monthly Tax Return PPh 21/26 in the Core Tax System

Indonesia's digital tax transformation through the Core Tax Administration System (CTAS) brings fundamental changes to tax reporting procedures. Based on Director General of Taxes Regulation Number PER-11/PJ/2025, the format of the Article 21/26 Income Tax Monthly Return (SPT Masa) involves total restructuring to accommodate data integration and administrative ease.

This article comprehensively reviews the form, content, and function of the new SPT Masa PPh 21/26 components.

Main Structure of SPT Masa PPh 21/26

In this new ecosystem, the SPT Masa PPh 21/26 is an electronic document serving as a means to report calculations, withholding slip creation, and tax payments. This SPT consists of two main elements: the Master Form (Induk) and Attachments (Lampiran).

1. Master Monthly Return (Induk SPT)

The Induk SPT is an executive summary of all withholding obligations in one tax period. Unlike the old forms, the Induk SPT in Core Tax will be pre-populated based on the data from the withholding slips created previously.

Key components in the Induk SPT include:

• Withholder Identity: Contains the NPWP, Name, Address, and Phone Number of the tax withholder.
• Article 21 Recapitulation: Summarizes the total PPh 21 withheld, overpayments from previous periods (compensation), payments via SP2D (for government agencies), and under/overpayment status.
• Article 26 Recapitulation: Presents a similar summary specifically for transactions with Non-Resident Taxpayers.
• Flexible Compensation: A flagship feature in the new Induk SPT is the compensation mechanism. If an overpayment occurs, the withholder can compensate it to the next tax period without having to be sequential. For example, an overpayment in January can be directly compensated to March or any other desired period,.

2. SPT Attachments: Four Pillars of Detail

To provide precise details, the SPT Masa is equipped with four new types of attachment forms replacing the old 1721-I form.

a. Form L-IA: Monthly Withholding List for Permanent Employees This form is used specifically to report PPh 21 withholding for Permanent Employees and Pensioners for every tax period other than the last tax period (generally January to November).

• Function: Recapitulates gross income and tax payable calculated using the Monthly Average Effective Rate (TER).
• Content: Contains details per employee including NIK/NPWP, Tax Object Code, Gross Income, TER Rate, and Tax Payable,.

b. Form L-IB: Last Tax Period Withholding List This is a crucial form that only appears in the Last Tax Period (December or the period when an employee resigns).

• Function: Reports the recalculation of annual tax using the Article 17 rate (not TER). This is where the final year-end underpayment or overpayment calculation occurs,.
• Content: Recapitulates the results from the BP-A1 or BP-A2 Withholding Slips created in that period.

c. Form L-II: One Tax Year Withholding List This form is an annual recapitulation covering the list of tax withholdings for one tax year or part of a tax year for permanent employees and pensioners. This form provides a helicopter view of all employee tax obligations for the year.

d. Form L-III: List of Withholding Other Than Permanent Employees This form accommodates all withholdings other than for permanent employees.

• Scope: Used to report withholdings using Form BP-21 (Experts, Event Participants, Non-Permanent Employees, Final Severance) and Form BP-26 (Non-Resident Taxpayers).
• Content: Recapitulates details of incidental or irregular transactions occurring in that month.

Conclusion

The form of SPT Masa PPh 21/26 in PER-11/PJ/2025 is designed to simplify compliance. With a clear separation between monthly reporting (L-IA) and the annual/last period reporting (L-IB), as well as data mechanisms integrated from withholding slips to the Master Form, the risk of input errors (human error) can be minimized. Tax withholders now only need to focus on the accuracy of creating withholding slips, as the SPT Masa is merely the downstream of that data.

Regulatory References:

1. Director General of Taxes Regulation Number PER-11/PJ/2025 concerning Provisions for Reporting Income Tax, VAT, and Stamp Duty within the Framework of Implementing the Core Tax Administration System.
2. Government Regulation Number 58 of 2023 concerning Article 21 Income Tax Withholding Rates.