
Expertise
BIR Audit & Tax Assessment Defense
Document-led counsel for BIR notices, assessments and corporate tax risk.

BIR Audit Defense & Tax Controversy
Document-led review and procedural assessment for active BIR matters.
Receiving a BIR Letter of Authority or other BIR document calls for prompt, document-specific review. Depending on the instrument and stage, the matter may lead to information requests, an assessment process, collection remedies, or separate proceedings under the National Internal Revenue Code (NIRC). NLF approaches BIR controversy through document review, procedural analysis, tax-law research, and litigation-oriented case assessment.
Nopuente Law Firm provides end-to-end BIR audit defense, from the initial LOA response through the Notice of Discrepancy (NOD), Preliminary Assessment Notice (PAN), Final Assessment Notice (FAN), and, where necessary, a Petition for Review before the Court of Tax Appeals (CTA). We do not guarantee specific outcomes, but we bring the same disciplined, document-first approach to every case that we developed through years of tax controversy practice.

Legal Basis
National Internal Revenue Code (NIRC), including Section 228, as amended
Primary authority governing assessments, protests, collection, and taxpayer remedies.
RMO No. 1-2026, as supplemented by RMO No. 6-2026 and RMC No. 14-2026
Current BIR audit-policy framework, including revised safeguards and the Single-Instance Audit Framework.
CTA Rules of Procedure (AM No. 05-11-07-CTA)
Governs appeals from BIR assessments to the Court of Tax Appeals.
Understanding the BIR Audit Process
A BIR audit may begin through the BIR's current electronic audit-authority process and can involve examination of records for identified taxable periods. The applicable audit controls, authorized personnel, document requests, and procedural safeguards must be assessed against the current BIR framework and the records issued for the specific matter. RMO No. 1-2026, together with later 2026 issuances, introduced a revised audit framework and a Single-Instance Audit Framework.
The audit process can move through several stages, each with its own procedural requirements and statutory deadlines. The correct response depends on the document received, the date and manner of receipt, the taxpayer's records, and the current applicable issuance. Missing an applicable statutory protest or appeal deadline can have serious consequences, including finality of an assessment and the commencement of collection remedies.
The most common deficiency findings in BIR audits involve undeclared income, disallowed expenses, VAT discrepancies between the Summary List of Sales/Purchases and the VAT returns, withholding tax deficiencies, and documentary stamp tax issues. Many of these findings arise not from intentional non-compliance but from technical documentation gaps, missing official receipts, invoices without the required information, or input VAT claims that cannot be substantiated.
The Assessment Timeline, Every Deadline Matters
Philippine tax procedure includes document-specific response, protest, and appeal periods. The correct step depends on the document received, the date and manner of receipt, the taxpayer's records, and the applicable current rules. A missed applicable deadline can materially affect available remedies.
- Notice of Discrepancy (NOD): Respond in writing within the period given (typically 30 days). This is your first opportunity to present documents and arguments.
- Preliminary Assessment Notice (PAN): A taxpayer generally has 15 days from receipt to submit a written response or reply. A PAN response is distinct from an administrative protest to a formal assessment.
- Final Assessment Notice (FAN) / Formal Letter of Demand (FLD): Section 228 provides a separate general 30-day period for an administrative protest, subject to the applicable rules and the facts.
- Protest route and supporting records: Reconsideration, reinvestigation, and supporting-document requirements should be evaluated under the current rules and the client's actual procedural posture.
- BIR Decision or Inaction: The available remedy and timing depend on the type of protest, the documents submitted, and the controlling provisions of the NIRC and applicable BIR and CTA rules.
- CTA Appeal: Appeal periods are strict and depend on the procedural route used. Obtain matter-specific advice promptly after a BIR decision, final demand, or relevant period of inaction.
Our Approach to BIR Audit Defense
Our first step in any BIR audit engagement is a thorough document review. We examine the LOA, the RO's audit working papers, and the taxpayer's books of accounts and returns to identify the factual and legal basis for each finding. We then prepare a written response that is specific, documented, and legally grounded, not a generic denial.
For assessments that proceed to the FAN stage, we prepare a formal protest that addresses each deficiency item individually, cites the applicable NIRC provisions, BIR issuances, and CTA jurisprudence, and attaches all supporting documents. Where the facts support it, we also explore settlement through a Compromise Agreement under Section 204 of the NIRC, which allows taxpayers to settle assessments at a reduced amount based on financial incapacity or doubtful validity of the assessment.
If the BIR denies a protest or does not act within the applicable period, we evaluate the procedural options recognized by the NIRC, current BIR rules, and jurisprudence. Under the relevant Section 228 and Lascona framework, the available choices and timing must be assessed carefully; they should not be reduced to a simple “whichever comes first” rule.
What We Handle
Frequently Asked Questions
Can I ignore a BIR LOA?
A BIR document should be reviewed promptly because different documents carry different procedural consequences and response periods. Management should identify the document, receipt date, taxable period, authorized scope, and next applicable deadline before deciding how to respond.
What is the difference between a Request for Reconsideration and a Request for Reinvestigation?
A Request for Reconsideration asks the BIR to re-evaluate its findings based on existing records, no new evidence is submitted. A Request for Reinvestigation allows you to submit new or additional evidence within 60 days. The choice affects the computation of the prescriptive period for BIR collection.
Can a BIR assessment be challenged?
A taxpayer may have protest, evidentiary, administrative, compromise, abatement, or appeal options depending on the assessment and the governing law. Any option must be assessed against the facts, documents, deadlines, and current BIR and CTA rules. Nopuente Law Firm does not guarantee a particular outcome.
How long does a BIR audit take?
There is no universal 120-day rule that makes every audit authority automatically lapse. Timing depends on the applicable BIR framework, the audit record, taxpayer submissions, statutory periods, and any ensuing protest or litigation. A current, matter-specific review is necessary.
Legal Disclaimer: The information on this page is for general informational purposes only and does not constitute legal advice. No attorney-client relationship is created by reading this page. Laws and regulations change; the information above reflects our understanding as of the date of publication and may not reflect subsequent amendments or new jurisprudence. Outcomes in legal matters depend on the specific facts and circumstances of each case. Nopuente Law Firm makes no guarantees of specific legal outcomes. Consult a qualified Philippine lawyer for advice on your specific situation.
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