In the Philippine jurisdiction, the duty to register a business with the Bureau of Internal Revenue (BIR) is not merely a formal step—it is a mandatory statutory obligation. Under Section 236 of the National Internal Revenue Code (NIRC), as amended, every person subject to any internal revenue tax must register with the appropriate Revenue District Office (RDO) on or before the commencement of business operations.

Failure to comply with this timeline triggers a series of administrative penalties, interests, and potential criminal liabilities.

1. The Statutory Deadline for Registration

According to BIR regulations (specifically Revenue Regulations No. 7-2012), a business must register:

For New Businesses: On or before the commencement of business.
Commencement of Business: This is defined as the day when the first sale transaction occurred or the day the Mayor’s Permit/Professional Tax Receipt (PTR) was issued, whichever comes first.
For Corporations/Partnerships: Within thirty (30) days from the issuance of the Certificate of Incorporation by the SEC.

2. Administrative Penalties (The "Compromise" Fees)

The BIR imposes "compromise penalties" in lieu of criminal prosecution for violations of the Tax Code. These are graduated based on the location and nature of the business, as outlined in Revenue Memorandum Order (RMO) No. 7-2015.

Business Classification	Penalty Amount (Approximate)
Cities	₱2,000 to ₱20,000
1st Class Municipalities	₱1,000 to ₱10,000
Other Municipalities	₱500 to ₱5,000

Note: The exact amount often depends on the "gross sales" or "asset size" of the entity as determined during the late registration process.

3. Civil Penalties and Interest

Late registration often implies that business operations were conducted without the payment of the Annual Registration Fee (ARF) and other applicable taxes.

Surcharge: A 25% surcharge is imposed on the basic tax due (e.g., the unpaid ₱500 Annual Registration Fee). If the failure to register is deemed "willful" or fraudulent, the surcharge jumps to 50%.
Deficiency Interest: Under the TRAIN Law (Republic Act No. 10963), the interest rate is set at double the legal rate set by the Bangko Sentral ng Pilipinas (currently effectively 12% per annum) on the unpaid amount until fully paid.

4. Failure to Issue Receipts and Keep Books

A primary consequence of late registration is that the taxpayer likely failed to issue registered Invoices/Receipts or maintain Books of Accounts. These are separate violations:

Failure to issue receipts: Penalties range from ₱1,000 to ₱50,000.
Failure to register books: Penalties range from ₱1,000 to ₱50,000 depending on the gross sales.
Issuance of unregistered receipts: This is considered a serious violation and can lead to higher fines or "Oplan Kandado" proceedings.

5. Criminal Liability

Under Section 258 of the NIRC, any person who fails to register with the BIR shall, upon conviction, be punished by:

A fine of not less than ₱5,000 but not more than ₱20,000; and
Imprisonment of not less than six (6) months but not more than two (2) years.

While the BIR typically settles these through administrative compromise penalties, the threat of criminal prosecution remains a legal reality for persistent non-compliance or tax evasion.

6. Oplan Kandado Program

The BIR’s "Oplan Kandado" program (Revenue Memorandum Order No. 3-2009) empowers the Bureau to suspend or temporarily close business operations. One of the primary grounds for "locking up" an establishment is the failure to register the business as required under Section 236. The closure remains in effect until the violation is rectified and the corresponding penalties are paid.

7. Summary of Rectification

To mitigate these penalties, taxpayers are encouraged to undergo Voluntary Compliance. By voluntarily approaching the RDO to register before an audit or "Tax Mapping" occurs, the taxpayer may negotiate for the minimum compromise penalties. Once a Mission Order is issued for tax mapping, the penalties are generally strictly applied at their maximum rates.