Quick answer

To contest a Bureau of Internal Revenue deficiency assessment, file a valid written administrative protest against the Formal Letter of Demand and Final Assessment Notice (FLD/FAN) within 30 calendar days from receipt. File it with the office of the Commissioner of Internal Revenue or the Commissioner’s authorized representative who issued the FLD/FAN.

Choose one remedy:

Request for reconsideration if the BIR should reevaluate the assessment using records already submitted; or
Request for reinvestigation if you will present newly discovered or additional evidence. Submit all supporting documents within 60 days from filing the protest.

Missing the 30-day protest deadline, filing with the wrong office, omitting required grounds, or failing to submit reinvestigation documents on time can make the assessment final, executory, and demandable. A response to a Preliminary Assessment Notice (PAN) does not replace the required protest against the later FLD/FAN.

These rules concern BIR deficiency assessments under the National Internal Revenue Code. Local business-tax assessments, real-property taxes, customs assessments, and tax-refund denials follow different procedures.

The deadlines at a glance

Event	What to do	Ordinary deadline
Receipt of PAN	Submit a written response explaining why the proposed assessment is wrong	15 days from receipt
Receipt of FLD/FAN	File a request for reconsideration or reinvestigation	30 days from receipt
Filing of request for reinvestigation	Submit all relevant additional supporting documents	60 days from filing
Denial by an authorized BIR representative through an FDDA	Appeal to the Commissioner or file a petition for review with the CTA	30 days from receipt
Denial by the Commissioner	File a petition for review with the CTA	30 days from receipt
BIR inaction for 180 days	Appeal the inaction to the CTA within the next 30 days, or wait for a final decision	See the rules below

The day of receipt is ordinarily excluded and the last day included. Calendar days are counted. If the last day falls on a legal holiday or other day when the receiving office is officially closed, special rules or a BIR extension may apply. Because tax deadlines are strictly enforced, file before the last day whenever possible. Do not assume that an office closure, typhoon, work arrangement, or request for extension changes the deadline unless an applicable official issuance says so.

There is no minimum peso amount required to use the Section 228 administrative-protest procedure or to appeal a disputed BIR assessment to the CTA.

Identify the document you received

Notice of Discrepancy or audit communication

During an audit, the BIR may invite the taxpayer to discuss discrepancies before issuing an assessment. Use this opportunity to correct factual errors, reconcile returns, and submit records, but do not mistake it for the formal protest stage.

Record the date received and keep the complete notice, attachments, envelope, and proof of service.

Preliminary Assessment Notice

A PAN states the BIR’s proposed deficiencies. It should explain in detail the facts and the law, regulations, or jurisprudence supporting the proposed assessment.

Respond in writing within 15 days from receipt. Address every tax type, taxable period, factual assumption, computation, and legal issue. Attach available documents and obtain proof of filing.

A PAN response is important but generally optional in the sense that failing to submit one does not eliminate the later right to protest a properly issued FLD/FAN. The BIR may issue the FLD/FAN if the taxpayer does not respond.

Formal Letter of Demand and Final Assessment Notice

The FLD/FAN is the assessment that must be protested under Section 228. It should state the facts and legal bases of the assessment and demand payment of the identified deficiency taxes and penalties.

Even if you believe the assessment is void—for example, because it lacks factual or legal bases, was issued late, or followed an unauthorized audit—file a timely protest and expressly raise those objections. Do not rely on the BIR or a court overlooking a missed deadline.

Final Decision on Disputed Assessment

An FDDA communicates the BIR’s action on a protested FLD/FAN. A valid FDDA should state:

The facts on which the decision is based;
The applicable law, regulations, or jurisprudence; and
That it is the official’s final decision.

A document’s title is not always decisive. A collection letter, final notice before seizure, warrant, or other communication may create urgent jurisdictional questions if it appears to be the BIR’s final action. Obtain legal advice immediately rather than waiting for another document.

When the BIR may issue an FLD/FAN without a PAN

Section 228 and Revenue Regulations No. 18-2013 permit an FLD/FAN to be issued without a PAN when:

The deficiency results from a mathematical error apparent on the face of the return;
There is a discrepancy between tax withheld and tax actually remitted by a withholding agent;
A taxpayer both claimed a refund or tax credit for excess creditable withholding tax and carried over the same amount to the succeeding taxable year;
Excise tax due on excisable articles was not paid; or
An article bought or imported by a tax-exempt person was sold, traded, or transferred to a non-exempt person.

Outside these exceptions, lack of a properly served PAN may be a due-process ground against the assessment. The Supreme Court has repeatedly required the BIR to observe the notice requirements, including actual or legally sufficient service. See CIR v. Avon Products Manufacturing, Inc., CIR v. Manila Medical Services, Inc., and CIR v. Fort 1 Global City Center, Inc..

How to prepare a valid protest

1. Establish the receipt date

The 30-day period begins from receipt, not merely from the date printed on the FLD/FAN.

Preserve:

The original envelope;
Registry receipt, return card, courier tracking, or delivery record;
The received stamp and date written on the notice;
The name, position, and authority of the person who received it;
Email or internal routing records showing when it reached the responsible officers; and
Evidence that the address used was or was not the taxpayer’s registered or known address.

Assessment notices may be served personally, by substituted service, or by mail under the applicable rules. Service on a properly authorized tax agent may be treated as service on the taxpayer. Refusing delivery is not a safe way to avoid the deadline. The BIR’s service procedures are detailed in Revenue Memorandum Order No. 40-2019.

2. Choose reconsideration or reinvestigation

A request for reconsideration asks the BIR to reevaluate the assessment using the existing record. Choose it when the decisive returns, reconciliations, receipts, contracts, and explanations have already been submitted and no additional evidence is needed.

A request for reinvestigation asks for reevaluation using newly discovered or additional evidence. The protest should identify the additional evidence you intend to present. All relevant supporting documents must be submitted within 60 days from filing.

The remedies are alternatives. Do not label the protest ambiguously. Under BIR guidance, a protest that does not clearly request reinvestigation may be treated as a request for reconsideration.

The distinction also affects the BIR’s 180-day decision period:

For reconsideration, the 180 days are counted from filing of the protest.
For reinvestigation, the 180 days are counted from submission of the required documents within the 60-day period.

3. Address every assessment item separately

For each tax type and taxable period, state:

The amount assessed;
Whether the item is disputed in full or only in part;
The material facts;
The specific error in the BIR’s factual assumption or computation;
The applicable statutory or regulatory provision;
Relevant controlling jurisprudence, if any; and
The document or schedule supporting the taxpayer’s position.

A bare statement that the assessment is “unjust,” “excessive,” or “without basis” is risky. The protest must identify its legal and factual grounds.

If an FLD/FAN contains several issues and the protest addresses only some of them, the unprotested items may become final, executory, and demandable. The same risk applies when an issue is mentioned but no facts or legal basis are given. If an amount is accepted, clearly identify it and arrange payment of that portion while expressly protesting the balance.

4. Check both the merits and the assessment process

Depending on the documents and facts, review possible grounds such as:

The income, sale, transaction, or withholding difference did not occur;
The BIR used the wrong tax rate, taxable base, period, classification, or mathematical computation;
Payments, withholding credits, carryovers, exemptions, or deductions were not properly credited;
The assessment rests on unreliable extrapolation, unsupported assumptions, or incomplete third-party data;
The PAN, FLD/FAN, or FDDA does not adequately explain the factual and legal bases;
A required notice was not properly served;
The audit was conducted by a revenue officer without a valid Letter of Authority or beyond its authorized scope;
A replacement revenue officer continued the examination without the required authority;
The FLD/FAN was issued outside the assessment period; or
The BIR did not meaningfully consider the taxpayer’s timely explanations and evidence.

An audit conducted without valid authority, or beyond the authority granted, can invalidate the resulting assessment. See CIR v. McDonald’s Philippines Realty Corporation and CIR v. Manila Medical Services, Inc..

The ordinary period for assessment is generally three years from the statutory due date of the return or its actual filing, whichever is later. Different rules may apply when no return was filed, when the BIR proves a false or fraudulent return within Section 222, or when the period was validly extended by written waiver. The ten-year exceptional period should not be assumed merely because the BIR alleges a discrepancy; its legal and factual basis must be examined. See CIR v. Asalus Corporation.

5. Attach an organized evidence set

Useful attachments may include:

Tax returns, amended returns, and proof of filing and payment;
Audited financial statements and tax-return reconciliations;
General ledgers, subsidiary ledgers, trial balances, and journal entries;
Invoices, official receipts applicable to the period, contracts, purchase orders, and delivery records;
Bank statements and payment records;
Withholding-tax certificates and validation of remittances;
Importation, excise-tax, or registration documents when relevant;
Prior submissions to the revenue officer;
The Letter of Authority and documents concerning reassignment of revenue officers;
The PAN, PAN response, FLD/FAN, schedules, worksheets, and prior BIR correspondence;
Sworn statements or third-party confirmations when legally and factually appropriate; and
A reconciliation schedule tying every attachment to the disputed item.

Use an index and page numbers. Submit legible copies, retain the originals, and keep an exact duplicate of everything filed.

Where and how to file

Address and file the protest with the office of the BIR official who issued the FLD/FAN—normally the relevant Regional Director, Assistant Commissioner, or other authorized higher revenue official. If the Commissioner issued it, file with the Office of the Commissioner.

Revenue Memorandum Circular No. 15-2020, Annex A recognizes filing:

In person, with a stamped received copy showing the date, office, and receiving officer; or
By registered mail, in which case the post-office mailing date is treated as the filing date and the envelope becomes part of the case record.

Do not send the protest to the auditing revenue officer, an unrelated RDO, or a general BIR email address and assume it was validly filed. Email alone is not a safe substitute unless a specific, applicable BIR issuance or written directive authorizes it.

If filing by registered mail, retain the registry receipt, tracking record, proof of contents, and return card. If filing personally, bring enough copies and check that every attachment is covered by the receiving stamp or acknowledgment.

What happens after filing

The BIR should evaluate the protest and issue an FDDA granting or denying it in whole or in part.

If an authorized representative of the Commissioner denies the protest, the taxpayer has two alternatives within 30 days from receipt:

File a petition for review directly with the Court of Tax Appeals; or
Elevate the protest to the Commissioner through a request for reconsideration.

An administrative appeal to the Commissioner is limited. No request for reinvestigation is allowed at that stage, and only issues addressed in the authorized representative’s decision will be entertained. File the administrative appeal with the Office of the Commissioner.

If the Commissioner denies the protest or administrative appeal, file the CTA petition within 30 days from receipt. A motion asking the Commissioner to reconsider that denial does not suspend or restart the 30-day CTA period.

What to do if the BIR does not decide within 180 days

When the applicable 180-day period expires without a decision, the taxpayer may:

Treat the inaction as a denial and file a petition for review with the CTA within 30 days after the 180-day period expires; or
Wait for the BIR’s final decision, then appeal that decision to the CTA within 30 days from receipt.

These choices are mutually exclusive. Once a taxpayer appeals the inaction, the taxpayer cannot also wait for and separately appeal the later administrative decision.

Waiting does not mean the protest has been granted, and BIR silence does not cancel the assessment. Maintain a reliable deadline calendar and preserve proof of the event from which the 180 days are counted. The Supreme Court confirmed these two alternatives in Lascona Land Co., Inc. v. CIR.

Appealing to the Court of Tax Appeals

A disputed-assessment appeal is initiated by a petition for review with the CTA in Division. The petition must comply with the Revised Rules of the CTA, applicable Rules of Court, filing-fee requirements, verification and certification rules, service requirements, and current paper and electronic-submission procedures.

Initiatory pleadings generally require paper filing by personal delivery, registered mail, or an accredited courier, together with the required electronic copy under the CTA’s current guidelines. Because noncompliance can result in a filing being treated as not filed, check the latest instructions on the CTA official website and its official downloads page before filing.

A corporation must act through properly authorized representatives and court counsel. Given the jurisdictional 30-day period and the technical requirements of CTA litigation, engage Philippine tax counsel early rather than waiting for the final week.

Does a protest or CTA appeal stop collection?

A timely and valid administrative protest ordinarily keeps the disputed assessment from becoming final and demandable while the protest remains properly pending. The undisputed portion, however, may be collected.

Once the matter reaches the CTA, filing an appeal does not automatically suspend collection. Under Section 11 of the law creating the CTA, the court may suspend collection when collection could jeopardize the interests of the government or the taxpayer. It may require a deposit of the amount claimed or a surety bond of not more than twice the amount, subject to recognized exceptions and the court’s orders.

If the BIR issues a collection letter, warrant of distraint or levy, garnishment notice, or seizure notice while a valid protest or administrative appeal is pending, seek legal assistance immediately. A motion to suspend collection may need to accompany or follow the CTA petition.

Interest may continue to affect the amount ultimately payable. Under Revenue Regulations No. 21-2018, the rate under Section 249 has been 12% per year since 2018, subject to any later change in the applicable BSP legal-interest rate. Computation also depends on the tax period and whether deficiency or delinquency interest applies.

Common mistakes that can lose the case

Protesting the PAN but failing to protest the FLD/FAN;
Counting from the date someone opened or internally forwarded the notice instead of the legally relevant receipt date;
Filing after the 30-day period;
Filing with the revenue officer or wrong BIR office rather than the issuing official’s office;
Calling the submission a “request for review” without clearly choosing reconsideration or reinvestigation;
Giving only general objections instead of facts and legal grounds for every issue;
Failing to identify additional evidence in a request for reinvestigation;
Submitting reinvestigation documents after the 60-day period;
Leaving some assessment items unprotested;
Assuming informal discussions, settlement talks, or follow-up letters extend a deadline;
Miscalculating the 180-day period;
Filing another motion with the Commissioner and assuming it tolls the CTA deadline;
Assuming a CTA appeal automatically stops distraint, levy, garnishment, or sale;
Discarding envelopes, return cards, registry receipts, or proof of filing; and
Relying solely on email when the applicable rules require personal or registered-mail filing.

When professional help is urgent

Consult a Philippine tax lawyer promptly if:

Fewer than 10 days remain before a 30-day or 60-day deadline;
The BIR disputes the receipt or filing date;
An FDDA or Commissioner’s decision has been received;
The taxpayer is considering an appeal based on 180 days of inaction;
A collection letter, garnishment, warrant of distraint or levy, or seizure notice has arrived;
The assessment invokes fraud, falsity, failure to file, or the ten-year period;
The audit may have been conducted without a valid Letter of Authority;
The assessment covers multiple taxes, taxable periods, related entities, or large amounts;
Important accounting records are missing or held by a former accountant;
Criminal investigation or referral is mentioned; or
The taxpayer may need a CTA order suspending collection.

A CPA can reconstruct records and test computations, but legal questions concerning validity, prescription, jurisdiction, and CTA appeals should be handled with tax counsel.

Frequently asked questions

Must I pay the assessment before filing an administrative protest?

Generally, no. Prepayment is not a condition for protesting a BIR deficiency assessment under Section 228. Any accepted or undisputed portion should be identified and paid. A later CTA appeal does not automatically stop collection.

Can I ask the BIR to extend the 30-day or 60-day period?

Do not rely on an extension. The ordinary assessment-protest periods are treated as mandatory. The BIR sometimes issues targeted extensions after disasters, suspensions of government work, or force-majeure events, but only taxpayers, offices, documents, and dates expressly covered by the issuance receive that relief.

What if the FLD/FAN contains no clear explanation?

Raise the defect in the protest and address whatever computations and allegations are available. Section 228 requires the taxpayer to be informed in writing of the facts and law on which the assessment is made; otherwise, the assessment may be void. The Supreme Court reaffirmed this requirement in CIR v. Elric Auxiliary Services Corporation.

What if I never received the PAN or FLD/FAN?

Gather address records, mail logs, affidavits, and evidence concerning the supposed recipient. When receipt is specifically denied, the BIR must establish legally sufficient service. Do not ignore later collection notices; they may be the first warning that the BIR considers the assessment final.

Should I choose reconsideration or reinvestigation?

Choose reconsideration only if the existing BIR record is sufficient. Choose reinvestigation if additional evidence is necessary and can be identified and submitted within 60 days. The choice should follow a document review, not merely a desire for more time.

Does the BIR’s failure to decide within 180 days mean I won?

No. It gives you a choice between appealing the inaction within the following 30 days and waiting for a final decision. Silence does not cancel the assessment.

Can I file the BIR protest by email?

The generally recognized methods are personal filing and registered mail with the issuing office. Do not depend on email alone without specific written authority applicable to the filing. CTA electronic-submission rules are separate from BIR administrative-protest rules.

What official rules should I check?

The principal sources are Section 228 of the National Internal Revenue Code, Revenue Regulations No. 18-2013, Revenue Regulations No. 7-2018, Revenue Memorandum Circular No. 15-2020, Annex A, and the Revised Rules of the Court of Tax Appeals.

This article provides general legal information, not legal or tax advice. The correct remedy may depend on the exact notices, dates, tax periods, signatories, service records, and evidence. Official sources and procedures were checked as of 10 August 2026.