Receiving a Bureau of Internal Revenue (BIR) Preliminary Assessment Notice can be alarming, especially when it claims that you owe substantial deficiency taxes, interest, and penalties. A PAN, however, is not yet a final tax assessment. It is the BIR’s written notice of its proposed findings and your opportunity to explain errors, present documents, and ask that the proposed assessment be withdrawn or reduced before a Formal Letter of Demand and Final Assessment Notice is issued.

The most important immediate step is to confirm when and how the PAN was received. Under current BIR rules, you generally have only 15 days from receipt to submit a written response. That period can pass quickly, so preserving proof of receipt, reviewing every assessment item, and filing a properly documented reply should take priority.

What Is a BIR Preliminary Assessment Notice?

A Preliminary Assessment Notice is a pre-assessment notice stating the BIR’s proposed deficiency taxes and the factual and legal grounds for those findings. It normally follows a tax audit, a Notice of Discrepancy, and a discussion between the taxpayer and the BIR examining team.

The PAN should identify:

The taxable period covered by the audit
The type of tax involved, such as income tax, value-added tax, withholding tax, or percentage tax
The BIR’s factual findings
The law, regulation, or jurisprudence supporting each finding
The proposed basic deficiency tax
Applicable interest, surcharge, and compromise penalties
The deadline and procedure for responding

A PAN is not yet a final demand for payment. It gives the taxpayer an opportunity to answer the proposed findings before the BIR issues a Formal Letter of Demand and Final Assessment Notice, commonly called an FLD/FAN. Under Revenue Regulations No. 18-2013, the taxpayer has 15 days from receipt of the PAN to respond. If no response is filed, the taxpayer is considered in default and the BIR may proceed with the FLD/FAN. (Supreme Court E-Library)

Although people commonly say they want to “protest a PAN,” the regulations technically distinguish between:

A response or reply to the PAN, filed within 15 days; and
An administrative protest against the FLD/FAN, filed within 30 days.

The Supreme Court emphasized this distinction in Commissioner of Internal Revenue v. Maxicare Healthcare Corporation. The 60-day period for submitting supporting documents in a reinvestigation applies to a protest against an FLD/FAN, not to the earlier PAN response. (Supreme Court E-Library)

Your Rights When the BIR Issues a PAN

The BIR must explain the factual and legal basis

Section 228 of the National Internal Revenue Code requires the taxpayer to be informed in writing of both the law and the facts on which an assessment is based. An assessment that does not satisfy this requirement may be void. The requirement is not met by merely listing Tax Code provisions, presenting unexplained computations, or making broad allegations without connecting them to the taxpayer’s records. (Supreme Court E-Library)

For example, a PAN alleging “undeclared sales” should ordinarily show how the BIR arrived at the alleged sales discrepancy. It should identify the records compared, the amounts involved, and the applicable tax treatment. A spreadsheet containing unexplained figures may not be enough if the taxpayer cannot reasonably understand and answer the finding.

In Ortiz Memorial Chapel, Inc. v. Commissioner of Internal Revenue, the Supreme Court reiterated that taxpayers must receive enough factual and legal detail to intelligently understand and contest an assessment. Broad legal citations and naked computations do not automatically satisfy due process. (Supreme Court of the Philippines)

The PAN should generally be limited to unresolved audit issues

Revenue Memorandum Order No. 1-2026 requires BIR audit personnel to document discrepancy discussions properly. The Notice of Discrepancy must clearly identify the issues raised, and subsequent assessment notices should be anchored on issues that remained unresolved after the discrepancy discussion. The BIR is also directed to request only documents directly relevant to the audit and within its authorized scope.

Compare the PAN with:

The Notice of Discrepancy
Minutes of the discrepancy discussion
Initial audit schedules
Documents previously submitted
Explanations already accepted or acknowledged by the examiners

A completely new issue appearing for the first time in the PAN should be identified in your response. Explain that you were not previously given a meaningful opportunity to discuss the issue, and request the complete factual basis and supporting computation.

The PAN must be properly served

Proper service matters because the 15-day response period ordinarily begins upon receipt. Revenue Regulations No. 18-2013 allows personal service, substituted service, and specified forms of mail or courier delivery. Service on an accredited tax agent may also be treated as service on the taxpayer. (Supreme Court E-Library)

In Mannasoft Technology Corporation v. Commissioner of Internal Revenue, the Supreme Court ruled that personal delivery of assessment notices must be made to the taxpayer or a duly authorized representative. Delivery to an employee or building personnel who had no authority to receive tax assessment notices was defective. The taxpayer’s later filing of a protest did not cure the invalid service. (Supreme Court of the Philippines)

Preserve evidence showing who actually received the PAN, including:

The original envelope and registry or courier records
The receiving copy or transmittal sheet
The recipient’s name and position
Company logbook entries
Security desk records
Emails or messages reporting the delivery
CCTV footage, when available and genuinely relevant
The recipient’s affidavit, if the circumstances become disputed

Do not ignore the PAN merely because service appears defective. Raise the defective-service issue in writing while also answering the substance of the proposed assessment.

When the BIR May Skip the PAN

Section 228 of the Tax Code and Revenue Regulations No. 18-2013 recognize limited situations in which a PAN is not required. The BIR may proceed directly to a final assessment when:

The deficiency resulted from a mathematical error apparent on the face of the return.
The amount of tax withheld did not match the amount actually remitted.
A taxpayer claimed a refund or tax credit but also carried over and applied the same amount against another tax liability.
Excise tax due on excisable articles was not paid.
An article locally purchased or imported under tax exemption was sold or transferred to a person who was not entitled to the exemption. (Supreme Court E-Library)

Outside these exceptions, the absence of a required PAN can be a serious due-process issue.

How to Count the 15-Day Deadline

The 15-day period begins from the date the PAN is received, not merely from the date printed on the notice. Under Article 13 of the Civil Code, the first day is excluded and the last day is included when computing a period. Unless a law states otherwise, “days” generally means calendar days. (Lawphil)

For example:

Event	Date
PAN actually received	July 1
First day counted	July 2
Fifteenth day	July 16

Do not assume that the deadline has been extended because you requested additional documents, spoke with the examiner, or were told informally that the BIR would wait. File before the original deadline unless you have a clear written directive from the authorized BIR office stating otherwise.

When there is uncertainty about the receipt date, use the earliest reasonably supportable date for internal deadline planning. A taxpayer should not risk losing the opportunity to respond while arguing over one or two days.

How to Respond to a BIR Preliminary Assessment Notice

1. Record the exact receipt details

Immediately write down:

The date and time of receipt
The person who received the PAN
Where it was delivered
The delivery method
The date your management, accountant, or lawyer actually learned of it

Scan the entire notice, including annexes, schedules, envelopes, registry receipts, and handwritten annotations. Keep the originals in a secure file.

2. Confirm the audit’s authority and scope

Review the Letter of Authority and other audit documents. Check:

The taxpayer name and Tax Identification Number
The taxable year or period covered
The taxes covered by the examination
The names of the authorized revenue officers
Whether the issuing office corresponds to the audit
Whether the proposed issues fall within the authorized scope
Whether the assessment may already be barred by prescription

As a general rule, the BIR has three years to assess a tax, counted according to the applicable Tax Code provisions. Longer periods may apply in cases involving a false or fraudulent return with intent to evade tax or failure to file a return. Prescription analysis is technical and should consider return-filing dates, waivers, amended returns, audit suspensions, and the exact assessment events.

3. Obtain all computations and annexes

A taxpayer cannot respond intelligently to missing or illegible schedules. Check whether the PAN contains:

Detailed deficiency-tax computations
Reconciliation schedules
Third-party information relied upon
Matching reports
Lists of allegedly undeclared transactions
Interest and penalty computations
References to specific invoices, customers, suppliers, or bank deposits

Request missing schedules promptly in writing. Nevertheless, do not allow the request to consume the 15-day period. Submit a timely response based on the available materials and identify precisely what was missing.

4. Build an issue-by-issue assessment matrix

A working table prevents important issues from being overlooked:

BIR finding	BIR amount	Your factual response	Legal basis	Supporting exhibit	Corrected amount
Alleged undeclared sales	₱___	Amount includes loan proceeds and inter-account transfers	Receipts are not automatically taxable sales	Bank reconciliation, loan agreement	₱___
Disallowed expense	₱___	Expense was ordinary, necessary, documented, and properly withheld	Applicable Tax Code provisions and regulations	Invoice, contract, proof of payment, BIR Form 2307	₱___
Withholding-tax discrepancy	₱___	Payment was exempt, accrued in another period, or already remitted	Applicable withholding rules	Alphalist, return, payment confirmation	₱___

Address every item, including alternative findings and penalty computations. An issue that appears small can affect related taxes, such as VAT, expanded withholding tax, and income tax.

5. Prepare a structured written response

A practical PAN response normally contains:

Heading and addressee. Address the BIR office and official identified in the PAN.
Taxpayer information. State the registered name, TIN, address, taxable period, and audit reference.
Receipt date. State when and how the PAN was received.
Position. Clearly say whether the taxpayer disagrees with the PAN in whole or in part.
Procedural objections. Raise lack of factual detail, defective service, prescription, authority issues, missing annexes, or issues not previously disclosed.
Issue-by-issue discussion. Use a separate heading for each proposed assessment.
Corrected computations. Reconcile the BIR figures with the taxpayer’s books and returns.
Supporting exhibits. Refer to numbered or lettered attachments.
Requested action. Ask the BIR to withdraw, cancel, or reduce the proposed assessment.
Signature and authority. Have the taxpayer or duly authorized representative sign.

Avoid a one-paragraph general denial. The response should explain exactly why each finding is factually or legally incorrect.

6. Attach organized supporting documents

Useful documents depend on the issue, but commonly include:

Issue	Possible supporting documents
Alleged undeclared income or sales	Sales ledgers, invoices, official receipts applicable to the audited period, contracts, delivery records, VAT returns, bank reconciliations
Bank deposits treated as income	Loan agreements, capital contribution documents, transfer records, deposit slips, intercompany reconciliations
Disallowed business expenses	Invoices, receipts, contracts, purchase orders, proof of delivery, proof of payment, withholding certificates
Withholding-tax findings	BIR Forms 1601, 2307, 2316, alphalists, payment confirmations, payee schedules
Payroll discrepancies	Payroll registers, employment contracts, time records, remittance records, employee master lists
Input VAT disallowance	VAT invoices, purchase journals, proof of payment, supplier information, import documents
Inventory discrepancies	Inventory counts, stock cards, cost records, wastage reports, transfer documents
Transactions with related parties	Agreements, invoices, transfer-pricing documentation, proof of actual services or deliveries
Previously paid tax	Filed returns, payment confirmations, tax credit certificates, proof of application

Number the attachments and prepare an exhibit index. Highlight relevant entries rather than submitting hundreds of pages without explanation. The goal is to show how each document answers a particular BIR finding.

7. File the response properly

Follow the filing instructions stated in the PAN. In practice, the response is usually submitted to the issuing BIR office or the authorized official handling the assessment.

For physical filing:

Bring at least two complete copies.
Have the BIR stamp your receiving copy with the date, office, and receiving personnel’s identification.
Confirm that all annexes were received.
Keep the stamped copy and an identical electronic scan.

For courier or registered-mail filing:

Use a traceable method.
Keep the mailing receipt, tracking record, envelope copy, and complete filed set.
Address the package exactly as instructed in the PAN.
Allow enough time to avoid disputes over lateness.

Do not rely solely on ordinary email unless the BIR office has expressly accepted electronic filing for that case. An examiner’s acknowledgment of an email does not always establish that a formally required submission was properly filed.

There is ordinarily no government filing fee for submitting a PAN response. The response itself is not generally required to be notarized, although affidavits, board resolutions, special powers of attorney, and other supporting instruments may require notarization or authentication.

8. Keep a complete audit record

Maintain one master file containing:

Letter of Authority
Notice of Discrepancy
Minutes of discrepancy discussions
PAN and all annexes
PAN response and supporting exhibits
Proof of filing
BIR emails and letters
Meeting notes
FLD/FAN, if later issued
Administrative protest and subsequent decisions

Tax disputes often turn on dates, service, documentary proof, and the exact position taken at each stage.

What Happens After You Reply to the PAN?

The BIR may:

Accept the explanation and cancel an issue
Reduce the proposed assessment
Request clarification or additional documents
Maintain some or all findings
Issue an FLD/FAN

A PAN response does not prevent the BIR from issuing an FLD/FAN. It gives the taxpayer an opportunity to correct the findings before the assessment becomes final.

The major procedural periods are:

Stage	General period
Response to Notice of Discrepancy	Up to 30 days from receipt under RR No. 22-2020
Response to PAN	15 days from receipt
Administrative protest against FLD/FAN	30 days from receipt
Supporting documents for a request for reinvestigation	60 days from filing the protest
BIR action on protest	180 days from the applicable reckoning point
Appeal to the Court of Tax Appeals	Generally 30 days from receipt of the denial, or from the expiration of the 180-day period when the taxpayer elects the inaction remedy

The Notice of Discrepancy is not itself an assessment. Current BIR audit rules require it to state the discrepancies clearly and require minutes of the discussion to be prepared and signed. (PwC)

If an FLD/FAN is issued, do not assume that the PAN response automatically serves as the required administrative protest. A separate, valid protest must generally be filed within 30 days from receipt of the FLD/FAN. The protest must state whether it is a request for reconsideration or reinvestigation and must identify the disputed issues and applicable legal grounds. (Supreme Court E-Library)

A request for reconsideration asks the BIR to reevaluate the assessment based on the existing records. A request for reinvestigation relies on newly discovered or additional evidence. For reinvestigation, supporting documents must generally be submitted within 60 days from filing the protest. (Supreme Court E-Library)

Common Mistakes When Answering a PAN

Missing the 15-day deadline

Waiting for the accountant, examiner, records custodian, or company headquarters can consume most of the response period. Begin reviewing the PAN on the day it is received.

When complete documentation cannot be gathered in time, file a substantive protective response using the available records. Identify the missing information, explain why it is material, and submit the documents as soon as possible. Do not claim that a later submission automatically extends the regulatory deadline.

Treating an informal meeting as the written response

A phone call, conference, chat message, or verbal explanation generally does not replace a properly filed written response. Put the taxpayer’s position and supporting evidence on record.

Sending documents without explaining them

A box of receipts or a large spreadsheet is not an argument. Explain what each exhibit proves, which BIR finding it answers, and how it affects the computation.

Failing to reconcile amounts

The strongest responses normally include reconciliations showing why the BIR and taxpayer figures differ. Common causes include timing differences, duplicated entries, cancelled transactions, non-income deposits, withholding credits, and differences between accounting and tax treatment.

Ignoring procedural defects

Even when the substantive tax issue can be answered, preserve objections involving:

Defective or unauthorized service
Lack of factual and legal basis
Missing schedules
Prescription
Improper audit authority
Findings beyond the authorized taxable period or tax type
New issues not raised during discrepancy discussions

Procedural objections should be stated clearly and supported by evidence. They should not be used as a substitute for addressing the merits when the merits can also be answered.

Confusing the PAN with the FLD/FAN

The PAN response deadline is generally 15 days. The FLD/FAN protest deadline is generally 30 days. Missing the later 30-day period may cause the assessment to become final, executory, and demandable. (Supreme Court E-Library)

The Supreme Court has recognized that an assessment void from the beginning for a fundamental due-process violation cannot become valid merely through the passage of time. However, this is an exceptional doctrine and should not be treated as permission to ignore statutory deadlines. File every response and protest on time whenever reasonably possible. (Supreme Court of the Philippines)

Special Considerations for Foreign Taxpayers and Overseas Officers

Foreign corporations registered or doing business in the Philippines, expatriates, and Philippine companies whose directors or authorized officers are abroad must pay particular attention to signing authority.

The BIR may require documents such as:

Secretary’s certificate or board resolution
Special power of attorney
Proof that the signatory is an authorized officer
Accreditation or authority of the tax agent
Government-issued identification
Foreign corporate records establishing the officer’s authority

A document signed and notarized abroad may need an apostille if it was executed in a country participating in the Apostille Convention. For documents from non-participating jurisdictions, consular authentication requirements may apply. The Philippines has applied the Apostille Convention since May 14, 2019. (Philippine Embassy New Delhi)

Because obtaining an apostille or consular authentication can take time, overseas signatories should arrange authority documents as soon as a BIR audit begins rather than waiting for the PAN.

Frequently Asked Questions

Is a Preliminary Assessment Notice already a final tax assessment?

No. A PAN contains proposed findings and gives the taxpayer an opportunity to respond. The final administrative assessment is ordinarily made through the FLD/FAN.

How many days do I have to answer a BIR PAN?

You generally have 15 calendar days from receipt of the PAN. The date of receipt is excluded when counting, while the last day is included. (Supreme Court E-Library)

Can I ask the BIR for an extension?

You may submit a written request explaining why additional time is needed, but you should not assume that the request suspends or extends the 15-day period. File your available substantive response within the original deadline unless an authorized BIR official gives a clear written extension that legally applies.

What happens if the PAN was received by a security guard or unauthorized employee?

Service may be defective if the notice was personally delivered to someone who had no authority to receive assessment notices for the taxpayer. Preserve proof of the recipient’s role and raise the issue immediately. At the same time, respond within the earliest possible deadline to avoid relying solely on the service argument. Mannasoft Technology Corporation v. CIR confirms that delivery to an unauthorized recipient can invalidate subsequent assessment action. (Supreme Court of the Philippines)

What if the PAN contains only computations and Tax Code citations?

State that the PAN does not adequately explain the factual and legal basis of the findings. Identify the missing information and request the underlying schedules. Also answer the proposed assessment as far as the available records permit. An assessment must provide enough detail for the taxpayer to understand and contest it intelligently.

Can the BIR include issues that were not in the Notice of Discrepancy?

Raise the issue in writing. Under current BIR audit policy, subsequent assessment notices should be anchored on discrepancies that remained unresolved after the discrepancy discussion. Ask the BIR to identify when the new issue was raised and what records support it.

Can I submit additional documents after the 15-day period?

The BIR may consider additional documents, but there is no automatic right to extend the PAN-response deadline merely because records are still being collected. File the response and available evidence on time, identify outstanding documents specifically, and submit them promptly.

Do I have to pay the proposed deficiency before responding?

A PAN is generally not yet the final enforceable assessment. You may dispute the proposed amount without first paying it. Payment may have legal and practical consequences, so verify what tax, period, and assessment stage a payment will cover before making it.

What should I do if I already missed the PAN deadline?

Determine whether an FLD/FAN has been issued. If none has been received, submit the PAN response immediately and preserve any explanation concerning receipt, defective service, or circumstances causing the delay. If an FLD/FAN has been received, prioritize the separate 30-day administrative protest deadline.

Does my PAN response count as a protest against the FLD/FAN?

No. A PAN response and an FLD/FAN protest are separate procedural steps with different deadlines. Filing a detailed PAN reply does not eliminate the need to file a proper administrative protest if the BIR later issues an FLD/FAN. (Supreme Court E-Library)

Key Takeaways

A BIR Preliminary Assessment Notice is a proposed assessment, not yet the final demand for payment.
A taxpayer generally has 15 calendar days from receipt to submit a written response.
Record the exact receipt date and preserve the envelope, delivery records, and identity of the recipient.
The PAN must state the specific factual and legal basis of each proposed deficiency.
Compare the PAN with the Notice of Discrepancy, discussion minutes, audit scope, and documents previously submitted.
Respond to every issue separately and support each answer with organized evidence and corrected computations.
File through a reliable, documented method and keep a complete stamped or traceable copy.
A PAN reply is not the same as the formal administrative protest required if an FLD/FAN is later issued.
If an FLD/FAN arrives, the taxpayer generally has a separate 30-day deadline to protest it.