Tax Reporting Transformation: List of Mandatory Documents and Attachment Mechanisms for Corporate Income Tax Returns in Coretax

Introduction

The implementation of the Core Tax Administration System (Coretax) brings fundamental changes to the reporting procedures for the Corporate Annual Income Tax Return (SPT Tahunan PPh Badan). Regulated in Director General of Taxes Regulation Number PER-11/PJ/2025, this system moves away from the digitized paper form approach (like e-Form PDF) towards a data-driven approach with an Induk-Centric (Master Form-Centric) concept.

One of the biggest questions for Corporate Taxpayers is: "What documents must I attach now?". In the old system, Taxpayers often had to scan stacks of thick documents to upload as a single PDF file. In Coretax, the definition of "attaching" has shifted. Most attachments that used to be separate documents have now been converted into structured data forms integrated directly into the Coretax web interface, while physical documents uploaded are limited to specific strategic documents.

This article will detail the list of documents and data attachments that must be prepared, the upload mechanism in Part I of the Master SPT, and a reporting case illustration to provide a real picture for Taxpayers.

"Induk-Centric" Concept and New Attachment Structure

Before getting into the document list, it is important to understand that in Coretax, Taxpayers no longer choose forms at the beginning. The system will ask a series of questions in the Master Form (Formulir Induk), and based on those answers, the system automatically "calls" or activates the relevant attachments.

Based on PER-11/PJ/2025, Corporate Annual SPT Attachments are classified into two main categories:

1. Data-Based Attachments (Digital Forms): Filled directly in the system (key-in) or data import (XML/Excel).
2. Document-Based Attachments (File Upload): Original documents uploaded in PDF format in the "Other Attachments" menu.

Detailed List of Mandatory Documents and Attachments

Here is a comprehensive breakdown of documents that must be prepared and attached according to the Taxpayer's condition:

1. Financial Statements (Mandatory for All Corporate Taxpayers)

Financial statements are the most crucial documents. In Coretax, reporting is divided into two steps:

• Data Conversion (Attachment 1): Taxpayers must copy figures from commercial Financial Statements into Attachment 1 (Financial Statement Reconciliation). Coretax provides various Attachment 1 variants according to business sectors, such as Attachment 1A (General), 1B (Manufacturing), 1C (Trading), to 1E (Bank).
• Upload Original Document: In Part I of the Master SPT, Taxpayers must upload the Financial Statement PDF file.
  • If audited, the uploaded file must be the Audited Financial Statements along with the Public Accountant's Opinion.
  • If having branches/subsidiaries abroad, must attach Consolidated Financial Statements.

2. Related Party Transaction Documents (Transfer Pricing)

For Taxpayers with transactions with affiliated parties, reporting obligations become stricter and more structured:

• Summary of Master & Local File (Attachment 10D): Taxpayers do not need to upload the thick Master File and Local File TP Doc in their entirety every year, but instead fill in the summary in the digital form Attachment 10D. However, the original documents must be available if requested at any time.
• CbCR (Country-by-Country Report): If the Taxpayer is the Parent Entity of a business group with a certain consolidated turnover, they must upload the Electronic Receipt of CbCR Submission in the other attachments menu.
• Attachments 10A, 10B, 10C: These are detailed data forms regarding counterparties, transaction values, and transfer pricing methods used.

3. Depreciation and Amortization List (Attachment 9)

The fixed asset list is no longer just a PDF attachment. Taxpayers must fill in Attachment 9 containing asset details per asset group.

• Coretax features allow last year's asset data to appear automatically (prepopulated).
• Taxpayers only need to update new asset data or assets disposed of/sold in the current year.

4. Article 25 Income Tax Calculation (For Certain Taxpayers)

According to PER-11/PJ/2025, General Taxpayers will calculate next year's Article 25 installments using Attachment 6. However, for Certain Taxpayers (Banks, SOEs, Regional SOEs, Public Listed Companies), they do not fill out Attachment 6 but are required to submit Article 25 Income Tax Installment Calculation Reports periodically (quarterly/semesterly) which are uploaded or reported through a separate menu integrated with the Annual SPT.

5. Foreign Tax Credit Documents (Attachment 3 & Upload)

If the Taxpayer has income from abroad and wants to credit the tax paid there (Article 24 Income Tax):

• Fill Data: Fill in details in Attachment 3.
• Upload Proof: Must upload copies of Tax Payment Proof or Withholding Slips from tax authorities/counterparties abroad in Part I of the Master SPT. Without this upload, the tax credit may be annulled by the system.

6. Nominative List of Expenses (Attachment 11A)

Certain sensitive expenses must be detailed in Attachment 11A, which covers:

• Nominative List of Promotional Expenses.
• Nominative List of Entertainment Expenses.
• List of Uncollectible Receivables (Bad Debt).
• New in Coretax: List of Assets/Facilities related to Benefits in Kind (Natura) (according to PMK 66/2023).

7. Tax Facility Documents (Attachment 13)

For Taxpayers utilizing facilities such as Tax Holiday, Tax Allowance, or Super Tax Deduction (Vocational/R&D):

• Must fill in Attachment 13A/13B/13C.
• Must upload supporting documents such as Facility Decree (SK) or Investment Realization Report if required by the system.

8. Debt and Equity Calculation (DER - Attachment 11B)

According to PMK-169/PMK.010/2015, Taxpayers must report the debt-to-equity ratio (Debt to Equity Ratio). In Coretax, this is facilitated through Attachment 11B. Taxpayers must fill in monthly debt and equity balance data to determine borrowing costs that are deductible and non-deductible.

Case Illustration: PT Manufaktur Sejahtera

To give a clear picture of how these documents are managed in Coretax, let's use the case study of PT Manufaktur Sejahtera.

Company Profile:

• Business Type: Textile Industry (Manufacturing).
• Turnover: IDR 60 Billion (Article 17 General Rate, not using PP 23).
• Bookkeeping: Audited by Public Accounting Firm.
• Special Transactions:
  • Import of raw materials (Has Article 22 Import Tax).
  • Paying royalties to the parent company in Singapore (Affiliate).
  • Providing official car facilities to Directors (Benefits in Kind).

Simulation Table of Document Reporting in Coretax

Workflow Analysis: In the case above, PT Manufaktur Sejahtera does not need to print physical 1771 forms. The only physical document that needs to be prepared in PDF format is the Auditor's Report. The rest is data input (or automatically pulled/prepopulated) into the Coretax digital forms.

Technical Document Upload Mechanism

The process of attaching PDF documents in Coretax is done at the final stage of filling the SPT, specifically in Master Form Part I (Other Attachments).

1. Navigation: After filling all relevant Attachments 1 to 15, the Taxpayer will return to the Master Form.
2. Part I: The system will display a checklist list of documents that must be uploaded based on the risk profile and previous entries.
   • Example: If in Part B "Audited Financial Statements" is selected, then in Part I an upload button for "Audited Financial Statements" will appear.
   • Example: If in Attachment 3 there is Foreign Tax Credit, the button to upload proof of foreign payment will be active.
3. Execution: Click the "+ Choose" or "Upload" button, find the PDF file on the computer, then upload. Ensure the file size does not exceed the limit determined by the system (usually limited per file, e.g., 5MB or 10MB depending on document type).
4. Validation: If mandatory documents are not uploaded, the "Save" or "Submit" SPT button will be locked (disabled), and the system will provide a validation error message.

Conclusion

Reporting Corporate Annual SPT in the Coretax era requires Taxpayers to be more organized in digital data administration. The list of documents "required to be attached" is now dominated by filling out structured data forms (Attachments 1-15) rather than just uploading scanned papers.

The keys to successful reporting are:

1. Master Data Validity: Ensure asset, affiliate, and shareholder data are updated so that the prepopulated feature works maximally.
2. Financial Statement Digitalization: Prepare detailed fiscal reconciliation working papers to facilitate input into Attachment 1.
3. PDF Preparation: Prepare Audited Financial Statements and foreign withholding slips in clear and readable PDF format before starting to fill out the SPT in the system.

By understanding this new structure according to PER-11/PJ/2025, Taxpayers can avoid the risk of SPT being considered incomplete (SPT Tidak Lengkap) which can lead to administrative sanctions.