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Worried About a BIR Audit? 5 Red Flags That Could Trigger One 

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Worried About a BIR Audit? 

Here Are 5 Red Flags That Could Trigger One in the Philippines 

Late filings? Mismatched tax reports? Missing receipts? These aren’t minor oversights — they’re red flags that could land your business in the middle of a BIR audit. 

The Bureau of Internal Revenue (BIR) doesn’t conduct audits randomly. They use risk profiling and data analytics to identify inconsistencies, gaps, or suspicious tax behavior — and issue audit letters accordingly. 

If you’re a business owner in the Philippines, here’s what to avoid (and how to prepare) in 2025. 

Red Flag #1: Late or Inconsistent Tax Filings 

Frequent delays or mismatched returns (e.g., high sales in VAT filings but low income tax declarations) raise suspicion. 

Example: You declare ₱5M in VAT sales, but your income tax return only shows ₱1M in revenue. The BIR may assume under-declaration and initiate a reconciliation audit. 

What to do: Ensure timely and consistent filing across all taxes — VAT, ITR, and Withholding Tax (WHT). Let a trusted tax consultant help reconcile and align your returns. 

Red Flag #2: Underreporting Sales or Overstating Expenses 

The BIR now cross-checks your filings with: 

  • e-invoicing systems 
  • Third-party data (e.g., from banks or suppliers) 
  • Digital marketplace records 

Reminder (RR No. 11-2018): All income and expenses must be fully documented and properly substantiated to be deductible. 

What to do: Don’t pad your expenses or hide sales. Maintain proper documentation, especially for fringe benefits, rentals, and subcontracted services. 

Red Flag #3: Failure to Issue or Keep Official Receipts 

The BIR requires: 

  • Issuing receipts/invoices for all sales 
  • Maintaining records for at least 10 years 

Marketplace receipts (e.g., from Shopee, Lazada) do not qualify as substitutes for official BIR-registered receipts. 

What to do: Set up proper books of accounts and ensure your ORs and invoices are registered and properly stored. 

Red Flag #4: Drastic Changes in Business Reporting 

Sudden drops in revenue or big jumps in expenses — without valid explanation — are red flags. 

Example: A business shows ₱12M in sales in 2024, then only ₱2M in 2025 — but doesn’t file for closure or dormancy. 

This can prompt BIR to investigate for undeclared income, ghost operations, or tax avoidance. 

What to do: If your business is slowing down or closing, file the proper deregistration with BIR, LGU, and SSS to avoid red flags. 

Red Flag #5: Using Unregistered Accounting Software 

Popular platforms like QuickBooks, Xero, or SAP are not automatically compliant with BIR rules. You must register them under: 

  • CAS (Computerized Accounting System) or 
  • CBA (Computerized Books of Accounts) 

Failure to register or report system changes (e.g., cloud migration, new features) can lead to audit notices. 

What to do: Register your software with the BIR and ensure it generates reports aligned with RR 09-2009 and updated e-invoicing regulations

Risks of a BIR Audit 

Risk Potential Impact 
Penalties & Surcharges For underpayment, late filing, or non-compliance 
Rejected Tax Deductions Due to lack of substantiation or mismatched returns 
Disrupted Operations Reconciliation and documentation requirements can take weeks 
Delayed VAT Refunds Refunds may be held until audit findings are resolved 
Legal Action In severe cases, businesses may face tax evasion cases 

How UNA Helps You Stay Audit-Ready 

At UNA Tax & Accounting Services, we work with Philippine businesses to: 

  • Catch errors before the BIR does 
  • Prepare documentation for fast response 
  • Ensure proper systems and filing processes are in place 
Mistake Risk How UNA Helps 
Late or inconsistent filing Audit notice, surcharges We track deadlines and ensure consistency 
No receipt-keeping Disallowed deductions We set up compliant documentation systems 
Overstated expenses Disallowed deductions, penalties We validate and document all tax claims 
Unregistered accounting tool System audit, non-compliance fines We manage CAS/CBA registration for your system 

Book a Tax Health Check Before the BIR Calls 

Don’t wait until an audit letter lands on your desk. Proactively assess your tax risks with UNA’s Tax Health Check a practical, confidential review of your tax filings, accounting systems, and documentation. 

Email us at: sales@una-acctg.com 

Let’s make sure your books are compliant, audit-ready, and stress-free.