A follow-up letter from the Direktorat Jenderal Pajak is not automatically a sign of wrongdoing. In many cases it is the DJP asking for clarification on a discrepancy between what a business reported and what the DJP's data sources show. The good news is that most of these discrepancies come from identifiable, preventable errors. The bad news is that once the letter arrives, you are on a clock to respond, and the investigation process is not something most business owners can navigate easily on their own.
Below are five mistakes that appear regularly in the tax filings of Indonesian small business owners. None of these are exotic edge cases. They are the ordinary oversights of people managing their own books under time pressure.
Mistake 1: Not reporting marketplace income
Since the DJP began receiving transaction data from major e-commerce platforms under various Peraturan Menteri Keuangan (PMK) data-sharing provisions, income earned through Tokopedia, Shopee, Bukalapak, Lazada, and similar platforms is visible to the tax office. If your SPT reports Rp 200 juta in business income but the DJP's data shows Rp 350 juta attributed to your NPWP via marketplace settlements, that gap will generate a clarification request.
The mistake is not intentional in most cases. Marketplace sellers track their top-line revenue but sometimes report their physical store income and forget the online channel entirely. Or they report the net settlement amount (after platform commissions) without reconciling it to the gross order value. The fix: pull a full annual settlement report from every platform where you sold goods, total it up, and ensure that figure is included in your reported peredaran bruto before you file.
Mistake 2: Treating capital purchases as immediate operating expenses
If you buy a Rp 25 juta refrigerator for your cafe or a Rp 15 juta sewing machine for your clothing alterations business, that is a capital expenditure, not an operating expense for that month. It should be capitalized and depreciated over its useful life according to the DJP's asset category schedule. For most equipment, the standard categories are group 1 (4 years, 25% per year) or group 2 (8 years, 12.5% per year).
Expensing a large capital purchase entirely in the year of purchase inflates your reported expenses and understates your taxable income. If the DJP's data shows you acquired a significant asset (bank transfers, supplier records, import documents) but your income statement shows no corresponding depreciation or asset entry, that inconsistency may prompt scrutiny. The right treatment is to record the asset at cost, establish the depreciation schedule, and claim only the applicable depreciation each year as a deduction.
Mistake 3: Claiming personal expenses as business deductions
This error is more common in businesses where the owner has not separated personal and business accounts. A personal grocery run, a family vacation, school fees for a child, a Netflix subscription, all recorded as business expenses because they were paid from the same account used for the business.
The DJP does not know, from the transaction record alone, that a particular payment was personal. But when they cross-reference your reported expenses against your revenue and typical industry expense ratios, personal expenses that inflate your Bahan Baku or Operasional categories distort the picture. The risk is not just that the deduction gets disallowed. It is that the overall pattern of your books looks unreliable, which can invite a broader examination. Clean account separation is the direct prevention for this error.
Mistake 4: Missing or inconsistent Bukti Potong documentation
When a client or counterparty withholds PPh 23 on a fee they pay you, they are required to provide a Bukti Potong documenting that withholding. You use that Bukti Potong as a tax credit in your annual SPT to reduce your total liability. If you report a credit for PPh 23 withholding in your SPT but the DJP cannot match it to a corresponding Bukti Potong filed by your counterparty, the credit may be questioned.
The most common variant of this mistake: you estimate the withholding credit based on what you believe was withheld, rather than the actual Bukti Potong amounts. The actual documents from your counterparties are the authoritative figures, not your calculations. Collect them from every client who withheld on your invoices before you file.
Mistake 5: Filing late or not at all
This one sounds obvious, but the SPT Tahunan deadline is missed by a meaningful number of individual taxpayers and business owners each year. For individual taxpayers with business income, the March 31 deadline is firm. Extensions are possible but require an explicit application submitted before the deadline, not after. Missing the deadline without an extension results in a late filing penalty (Rp 100 ribu for individual taxpayers, Rp 1 juta for corporate entities) plus, more significantly, it places your filing in a late status that makes any subsequent amendment or correction more complex to process.
Not filing at all is a different category of problem. The DJP has mechanisms to issue a deemed assessment based on available data when a taxpayer fails to file. The deemed assessment is unlikely to be favorable compared to what you would have filed yourself, because it does not account for your deductions. It can also trigger penalties that accumulate over time.
The businesses that consistently file on time and without errors tend to have one thing in common: they are not doing their annual filing for the first time in late February. They have organized records from the prior year, they know approximately what they owe, and filing is a matter of confirming numbers that are already largely known. The preparation happens during the year. The filing is just the conclusion.