Quick answer
If you receive a BIR Formal Letter of Demand and Final Assessment Notice (FLD/FAN) and disagree with it, you generally have 30 days from receipt to file a valid written administrative protest. The protest must be either a request for reconsideration or a request for reinvestigation, must identify the assessment being challenged, and must state the factual and legal grounds for each disputed issue. A generic letter saying that you “disagree” or asking the BIR to “reconsider” may not be enough. If no valid protest is filed within the 30-day period, the assessment generally becomes final, executory, and demandable.
A request for reconsideration asks the BIR to re-evaluate the assessment using the existing records. A request for reinvestigation relies on newly discovered or additional evidence. If you choose reinvestigation, the relevant supporting documents must generally be submitted within 60 days from filing the protest. The 60-day document deadline does not apply to a reconsideration.
Do not confuse a response to a Preliminary Assessment Notice (PAN) with the formal protest against an FLD/FAN. A taxpayer ordinarily has 15 days from receipt of the PAN to respond, while the formal Section 228 protest is directed against the FLD/FAN.
These deadlines are jurisdictionally important once a dispute reaches the Court of Tax Appeals (CTA). The Supreme Court has held that a taxpayer who goes to the CTA without first making a valid administrative protest may have the case dismissed for lack of jurisdiction. (E-Library)
Know which BIR notice you received
A tax audit can generate several documents, and the correct response depends on the document actually served.
A PAN gives the BIR's proposed findings and should state the facts and legal basis for them. Under Revenue Regulations No. 18-2013, the taxpayer ordinarily has 15 days from receipt to respond.
A PAN is not required in the specific exceptions stated in Section 228 and RR No. 18-2013: a mathematical error appearing on the face of the return; a discrepancy between tax withheld and tax actually remitted; double use of excess creditable withholding tax through both a refund/tax-credit claim and carry-over; unpaid excise tax on excisable articles; and the sale, trade, or transfer to a non-exempt person of an article acquired or imported by an exempt person. In those situations, the BIR may issue an FLD/FAN outright. (E-Library)
The FLD/FAN is the assessment that must be formally protested. It should state the facts and the law, rules, regulations, or jurisprudence on which the assessment is based. The taxpayer generally has 30 days from receipt to file the administrative protest. (E-Library)
An FDDA, or Final Decision on Disputed Assessment, is the BIR's decision on the protested assessment. If the decision comes from a duly authorized representative of the Commissioner, RR No. 18-2013 provides further administrative and judicial options. If the decision is already that of the Commissioner of Internal Revenue, a different and particularly strict CTA deadline applies.
Receipt matters. BIR rules permit personal, substituted, and mail service, and service on a properly appointed tax agent may be deemed service on the taxpayer. For registered mail, the BIR's service rules can make the legally relevant date different from the day somebody eventually retrieves the envelope. Preserve the envelope, registry notices, courier records, receiving stamps, and other proof showing how and when the notice was served. (Bir Cdn)
The deadlines that matter
| Stage | General deadline or period |
|---|---|
| Response to PAN | 15 days from receipt of PAN |
| Protest against FLD/FAN | 30 days from receipt of FLD/FAN |
| Supporting documents for reinvestigation | 60 days from filing the protest |
| BIR action period on a reconsideration before the authorized representative | 180 days from filing the protest |
| BIR action period on a reinvestigation before the authorized representative | 180 days from submission of the required documents, which must be submitted within the 60-day period |
| Denial by a duly authorized representative | Generally 30 days from receipt to appeal directly to the CTA or elevate the protest by request for reconsideration to the Commissioner |
| Denial by the Commissioner | 30 days from receipt to appeal to the CTA; another motion for reconsideration does not suspend this CTA deadline |
| BIR inaction after the applicable 180-day period | Taxpayer may appeal to the CTA within the following 30 days, or elect to await the final BIR decision and appeal that decision within 30 days of receipt (E-Library) |
The two remedies following BIR inaction are mutually exclusive. If the taxpayer elects to appeal the inaction, the CTA filing must be made within the applicable 30-day window. If the taxpayer instead genuinely elects to await the final BIR decision, the taxpayer may appeal that later decision within 30 days from receipt. Silence for 180 days does not mean that the taxpayer automatically wins. (E-Library)
There is no general minimum peso amount before a taxpayer may use the Section 228 administrative protest procedure. The critical requirements are the existence of a protestable assessment, a timely filing, and compliance with the required form and grounds. (E-Library)
Current 2026 filing note: RMC No. 35-2026 provides that, while RMO No. 007-2026 remains effective, when the deadline for a request for reconsideration of an FDDA within the BIR National Office falls on a Friday, the filing deadline moves to the next business day when National Office personnel are working on-site. The circular does not alter the substantive requirements for the request. Because this arrangement is tied to an operational BIR issuance and may later change, verify the current BIR schedule before relying on it.
Step-by-step: protesting an FLD/FAN
Determine the exact date and manner of service. Record when the FLD/FAN was personally received, delivered, mailed, or otherwise served. Preserve the envelope, registry notice, courier tracking, receiving stamp, email or internal routing record, and the identity of the person who received it. Do not automatically assume that the day management first saw the document is the legally controlling receipt date. (Bir Cdn)
Break the assessment down by tax type, taxable period, and issue. Compare the PAN, FLD/FAN, schedules, audit working papers or explanations furnished by the BIR, filed returns, books, withholding records, invoices, receipts, contracts, and other source documents. A protest should address each contested adjustment rather than treating the assessment as one undifferentiated amount.
Choose between reconsideration and reinvestigation deliberately. A reconsideration relies on the existing records. A reinvestigation is appropriate when newly discovered or additional evidence will be presented. If reinvestigation is selected, identify in the protest the additional evidence intended to be submitted.
Prepare a legally sufficient written protest. RR No. 18-2013 requires the protest to state whether it is for reconsideration or reinvestigation, identify the date of the assessment notice, and state the applicable law, rules, regulations, or jurisprudence supporting the protest. The factual and legal basis for the objections should be stated issue by issue. A protest that fails the required elements may be treated as void and without force or effect.
Expressly dispute every issue you intend to contest. If an FLD/FAN contains several issues and the taxpayer disputes only some of them, the assessment attributable to the undisputed issues becomes final, executory, and demandable. The regulations similarly treat an issue as undisputed when the taxpayer purports to contest it but fails to state the facts and applicable legal basis supporting the objection.
File the protest with the proper BIR office and obtain reliable proof of filing. BIR RMC No. 11-2014 directs responses to PANs and protests against FLD/FANs to the duly authorized representative who signed the relevant notice. An administrative request for reconsideration elevated to the Commissioner is filed with the Office of the Commissioner. Preserve a stamped receiving copy or other official evidence establishing timely filing. (Bir Cdn)
If you chose reinvestigation, complete the evidence submission within 60 days. Do not treat this as an informal or extendible evidence-gathering period. The Supreme Court has likewise recognized that a taxpayer requesting reinvestigation is entitled to the full 60-day period contemplated by the governing regulations to submit relevant supporting documents. (Lawphil)
Calendar the correct 180-day period. For a reconsideration before the Commissioner's authorized representative, RR No. 18-2013 counts the 180 days from filing of the protest. For a reinvestigation, it counts from the submission of the required documents within the 60-day period. Do not use the wrong starting date when calculating a possible CTA appeal from inaction.
When an adverse decision arrives, identify who issued it before choosing the next remedy. If the protest is denied by the Commissioner's duly authorized representative, RR No. 18-2013 permits the taxpayer, within 30 days from receipt, either to appeal directly to the CTA or to elevate the matter by request for reconsideration to the Commissioner. A reinvestigation is not available at that administrative-appeal stage.
Once the Commissioner denies the protest or administrative appeal, protect the CTA deadline. The taxpayer generally has 30 days from receipt of the Commissioner's decision to appeal. Filing another motion asking the Commissioner to reconsider does not toll that 30-day period.
What evidence should you preserve?
The entire assessment package matters. Keep the Letter of Authority, notices, schedules and annexes, PAN, response to PAN, FLD/FAN, protest, documentary submissions, conference records, FDDA, collection letters, and all attachments. Whether the BIR adequately explained an assessment may depend on the written record as a whole.
Proof of receipt and proof of filing can decide the case before the merits are even reached. Keep registry cards, postmaster notices, envelopes, courier tracking, receiving stamps, affidavits or internal records identifying who accepted service, and the BIR-received copy of every submission. The BIR has specific rules on personal, substituted, and mail service. (Bir Cdn)
Preserve the accounting trail behind each disputed adjustment. Depending on the issue, this may include tax returns and attachments, general and subsidiary ledgers, trial balances, invoices, official receipts or other valid sales documents, withholding certificates, bank records, payroll records, contracts, import documents, inventory records, reconciliations, and proof of tax payments.
Keep documents relating to prescription. If the timeliness of the assessment is disputed, preserve the original return and proof of filing, amended returns, the FLD/FAN and evidence concerning when it was issued, and every waiver or alleged waiver of the statute of limitations together with evidence of the authority of the persons who signed it.
Grounds worth checking before you finalize the protest
The BIR's computation or factual assumptions may be wrong
Many protests turn on ordinary but consequential factual questions: whether income was counted twice, whether a payment or withholding credit was omitted, whether an expense was disallowed on an incorrect factual premise, whether transactions were assigned to the wrong taxable period, or whether the BIR's reconciliation can be traced to the taxpayer's books.
A strong protest normally does more than deny the finding. It explains the correct treatment, reconciles the numbers, identifies the supporting documents, and ties the position to the governing tax provision or regulation.
The assessment must disclose its factual and legal basis
Section 228 requires taxpayers to be informed in writing of the law and facts on which an assessment is made, and RR No. 18-2013 similarly requires an FLD/FAN to state its factual and legal bases. This is a substantive due-process protection because a taxpayer cannot meaningfully protest an unexplained assessment. (E-Library)
But avoid assuming that every imperfectly written notice is automatically void. Supreme Court jurisprudence examines the actual written communications and circumstances. In CIR v. Liquigaz Philippines Corp., the Court addressed when the required factual and legal bases were sufficiently communicated and also emphasized that a defective FDDA does not necessarily invalidate the underlying assessment itself. The validity question therefore depends on the particular PAN, FLD/FAN, FDDA, attachments, and written exchanges in the case. (E-Library)
The assessment may have been issued beyond the allowable period
As a general rule under Section 203 of the Tax Code, internal revenue taxes must be assessed within three years after the last day prescribed for filing the return; if the return was filed late, the period generally runs from the actual filing date. A return filed early is generally treated as filed on the statutory due date for this purpose. (E-Library)
That three-year rule has major exceptions. Section 222 permits assessment within 10 years after discovery in cases involving a false or fraudulent return with intent to evade tax or failure to file a return. The assessment period may also be extended through a valid written agreement made within the applicable period. Whether a return is legally “false” or “fraudulent,” whether the extended period applies, and whether a waiver is valid are fact-sensitive questions that should not be assumed from the size of the alleged deficiency alone. (E-Library)
The BIR may have failed to follow required assessment procedures
Review whether a PAN was required, whether it was properly served, whether the taxpayer was given the required opportunity to respond, whether the FLD/FAN contained the required factual and legal basis, and whether an FDDA was prematurely issued during a valid reinvestigation.
One caution is important: RR No. 18-2013 says that, after a taxpayer responds to a PAN, the FLD/FAN should be issued within 15 days. BIR RMC No. 11-2014 clarifies, however, that issuance beyond that 15-day administrative period does not by itself invalidate the FLD/FAN, provided the assessment was issued within the applicable statutory limitation period. (Bir Cdn)
Other questions—such as the validity, scope, and implementation of a Letter of Authority—can also be material, but the governing doctrine is highly dependent on the specific audit record and personnel involved. Those issues should be analyzed from the actual documents rather than raised as boilerplate objections.
What happens if the BIR does nothing for 180 days?
BIR inaction is not an automatic cancellation of the assessment.
Under the regulations and Supreme Court jurisprudence, after the applicable 180-day period expires, the taxpayer generally has two alternatives: appeal the inaction to the CTA within the following 30 days, or await the BIR's eventual final decision and appeal that decision within 30 days from receipt. (E-Library)
The alternatives are mutually exclusive. A taxpayer who chooses an appeal from inaction must comply with the deadline governing that chosen remedy. Conversely, the Supreme Court has repeatedly recognized that a taxpayer who elects to wait cannot be prejudiced merely because the BIR took longer than 180 days to decide. (E-Library)
This choice can have major procedural and litigation consequences. Before the 180-day point arrives, calculate the period carefully and decide consciously whether to go to the CTA or continue waiting for a final administrative decision.
Does filing a protest stop BIR collection?
A timely and valid administrative protest prevents the disputed assessment from becoming final merely because the initial 30-day protest period expired. However, undisputed portions of a multi-issue assessment can become final, executory, and demandable.
Once the matter reaches the CTA, filing a petition for review does not automatically suspend collection. Under Section 11 of the CTA law, an appeal generally does not suspend payment, levy, distraint, or sale. The CTA may, in appropriate circumstances, suspend collection when the statutory requirements are met, and the law authorizes the Court to require a deposit or surety bond of up to twice the amount claimed. (E-Library)
Accordingly, a taxpayer who has received a warrant, bank garnishment, levy notice, or other active collection measure should not assume that an administrative or CTA filing alone has frozen enforcement.
Common mistakes
Treating the PAN response as the formal protest. The PAN ordinarily calls for a response within 15 days. The statutory administrative protest is directed against the FLD/FAN and has its own 30-day deadline.
Sending a generic objection letter. In Citysuper, the Supreme Court stressed the consequence of failing to make a valid protest complying with the governing requirements. State the nature of the protest, assessment date, factual grounds, and applicable legal authorities instead of relying on a bare request for reconsideration. (E-Library)
Choosing reinvestigation and missing the 60-day document deadline. If additional evidence is necessary, organize it before the protest is filed and calendar the statutory period immediately.
Failing to contest every adjustment. An unchallenged issue—or an issue supposedly challenged without supporting facts and legal grounds—may be treated as undisputed and become final and demandable.
Assuming 180 days of BIR silence means the assessment disappeared. It does not. The taxpayer instead faces a procedural choice between appealing the inaction within the applicable CTA window and waiting for the final BIR decision. (E-Library)
Filing another motion after the Commissioner has denied the case and assuming the CTA clock stopped. RR No. 18-2013 expressly provides that a motion for reconsideration of the Commissioner's denial does not toll the 30-day period for CTA appeal.
Assuming a CTA appeal automatically stops collection. It does not. Separate relief from collection may have to be sought from the CTA. (E-Library)
Losing proof of receipt or filing. Because many tax cases turn on whether a 15-, 30-, 60-, or 180-day period was correctly calculated, the envelope, registry notice, receiving stamp, and proof of filing can be as important as the substantive tax arguments.
When professional help is urgent
Seek tax counsel or other qualified professional assistance promptly if the 30-day FLD/FAN protest deadline is approaching, if an FDDA or other adverse decision has already been received, or if the applicable 180-day period is about to expire and a CTA strategy must be chosen.
Assistance is particularly urgent when the BIR has begun collection through a warrant of distraint or levy, bank garnishment, or other enforcement measure; when the assessment includes allegations of fraud or falsity; when prescription depends on waivers or disputed filing dates; when substantial penalties are involved; or when there are questions about whether the assessment itself was validly issued or served.
CTA litigation is highly procedural. A strong tax position on the merits cannot necessarily cure a missed administrative protest or judicial appeal deadline.
FAQ
Can I protest a PAN?
You may and ordinarily should respond to a PAN within 15 days if you disagree with its findings. Technically, however, the formal administrative protest contemplated by Section 228 and RR No. 18-2013 is the protest against the subsequently issued FLD/FAN.
Do I have to pay the full assessment before filing a protest?
The Section 228 protest procedure does not impose full payment of the disputed assessment as a condition for filing a valid administrative protest. However, if an FLD/FAN contains several issues and you leave some undisputed, the corresponding assessment for those issues becomes final, executory, and demandable.
Should I request reconsideration or reinvestigation?
Use reconsideration when the assessment can be resolved from the existing record and legal arguments. Use reinvestigation when you need the BIR to consider newly discovered or additional evidence. The choice affects both the 60-day document requirement and the reckoning of the 180-day action period, so it should be deliberate.
What if I discover additional documents after filing a reconsideration?
That can create a procedural problem because reconsideration is defined as re-evaluation based on existing records, while reinvestigation is the remedy based on newly discovered or additional evidence. The consequences will depend on the stage of the case and what was actually filed. Do not assume that the BIR or CTA must accept new evidence merely because it supports the merits of the assessment dispute.
What if the BIR does not decide my protest within 180 days?
You may generally appeal the inaction to the CTA within the next 30 days or choose to await the BIR's final decision and later appeal that decision within 30 days from receipt. The two routes are mutually exclusive once one is chosen. (E-Library)
Can I ask the Commissioner to reconsider after receiving an FDDA from an authorized BIR representative?
Generally, yes. RR No. 18-2013 allows the taxpayer, within 30 days from receipt of a denial by the Commissioner's duly authorized representative, either to appeal directly to the CTA or to elevate the protest by request for reconsideration to the Commissioner. A reinvestigation is not allowed at this administrative-appeal stage.
Can I file another motion for reconsideration after the Commissioner denies the protest?
You may face serious consequences if you rely on such a motion. RR No. 18-2013 expressly states that a motion for reconsideration of the Commissioner's denial does not toll the 30-day period for appealing to the CTA.
Is an assessment automatically void if the FAN or FDDA contains little explanation?
Not necessarily. Section 228 requires written disclosure of the factual and legal basis, and failure to satisfy due process can invalidate an assessment or decision. But Supreme Court cases examine the actual documents and communications, and a defective FDDA does not automatically make the underlying assessment void. Review the PAN, FLD/FAN, schedules, attachments, protest correspondence, and FDDA together. (E-Library)
Does the BIR always have only three years to assess?
No. Three years is the general rule under Section 203, but Section 222 contains exceptions, including false or fraudulent returns with intent to evade tax, failure to file a return, and valid written agreements extending the assessment period. (E-Library)
Does filing with the CTA stop BIR collection?
No, not automatically. The CTA has statutory authority to suspend collection in proper cases, but judicial relief must be sought and the Court may impose conditions permitted by law. (E-Library)
Official sources
National Internal Revenue Code, Section 228 and related provisions: Republic Act No. 8424 — Supreme Court E-Library
BIR rules governing PANs, FLD/FANs, protests, FDDA decisions, and administrative appeals: Revenue Regulations No. 18-2013 — BIR official PDF
BIR clarifications on where protests are filed, reinvestigation documents, and post-PAN procedures: Revenue Memorandum Circular No. 11-2014 — BIR official PDF
Rules on service of PANs, FLD/FANs, and FDDAs: Revenue Memorandum Order No. 40-2019 — BIR official PDF
Current 2026 clarification for certain Friday National Office filing deadlines: Revenue Memorandum Circular No. 35-2026 — BIR official PDF
Current BIR energy-conservation/work-arrangement issuance referenced by RMC No. 35-2026: Revenue Memorandum Order No. 007-2026 — BIR official PDF
Supreme Court ruling on the need for a valid administrative protest: CIR v. Court of Tax Appeals and Citysuper, Inc., G.R. No. 239464, May 10, 2021 — Supreme Court E-Library
Supreme Court ruling on the 60-day reinvestigation document period: CIR v. Maxicare Healthcare Corporation, G.R. No. 261065, July 10, 2023 — Lawphil
Supreme Court ruling on BIR inaction and the option to await a final decision: Lascona Land Co., Inc. v. CIR, G.R. No. 171251, March 5, 2012 — Supreme Court E-Library
Supreme Court ruling concerning the factual and legal basis of an FDDA: CIR v. Liquigaz Philippines Corporation, G.R. Nos. 215534 and 215557, April 18, 2016 — Supreme Court E-Library
General-information disclaimer
This article provides general information on Philippine tax law and procedure and is not legal, tax, or accounting advice for any particular assessment. Tax protests are deadline-sensitive, and the correct remedy can depend on the exact notice, manner and date of service, taxable period, evidence, identity of the BIR official who issued the decision, prior filings, and procedural history. Review the actual assessment documents and obtain case-specific advice when necessary.
Sources checked as of August 25, 2026. BIR regulations, circulars, work arrangements, filing procedures, and Supreme Court or CTA rules may be amended or superseded after that date, so current official issuances should be verified before filing.