Commissioner of Internal Revenue vs. Court of Appeals

The ad valorem tax on mineral products sold abroad under C.I.F. terms is computed based on the actual market value of the mineral in its condition at the time of extraction; where the manufactured product's price (e.g., LME price of copper wire bars) is used as the reference, all costs of post-extraction processing (smelting, refining, fabricating) must be deducted to approximate the value of the raw mineral at the mine site.

Atlas Consolidated Mining and Development Corporation (ACMDC) operated a mining concession in Toledo City, Cebu, exporting copper concentrates to Japan. The Bureau of Internal Revenue (BIR) issued deficiency tax assessments for 1975 and 1976, covering ad valorem taxes, surcharges, manufacturer's sales tax, and contractor's tax. ACMDC protested the assessments, leading to consolidated petitions before the Court of Tax Appeals (CTA). The CTA largely ruled in favor of ACMDC on the ad valorem tax computation but held it liable for certain surcharges and other taxes. Both parties appealed to the Court of Appeals (CA), which further modified the CTA decision. The cases were elevated to the Supreme Court via separate petitions.

• Nature of the Action: The cases involve deficiency tax assessments for ad valorem taxes, surcharges, manufacturer's sales tax, and contractor's tax against ACMDC for 1975 and 1976.
• The Assessments: The BIR assessed ACMDC for deficiency ad valorem taxes on copper and silver, plus surcharges for late payment/filing, and for manufacturer's sales tax and contractor's tax.
• ACMDC's Position: ACMDC protested, arguing that smelting and refining charges should be deducted from the LME price of copper wire bars to determine the taxable base for ad valorem tax on copper concentrates. It also contested the surcharges and other taxes.
• CTA Decision: The CTA deleted the bulk of the ad valorem tax, agreeing with ACMDC's computation method, but held ACMDC liable for surcharges on silver, gold, and pyrite, and for manufacturer's sales tax and contractor's tax.
• CA Decisions: The CA affirmed the CTA on the ad valorem tax issue. In the second appeal, it deleted some surcharges for 1975 but upheld others for 1976, and upheld the manufacturer's and contractor's taxes.
• Supreme Court Proceedings: Both parties appealed to the Supreme Court, challenging different aspects of the CA rulings.

• Ad Valorem Tax Base (Commissioner): The Commissioner argued that the actual market value of copper concentrates should be the gross sales realized, with deductions allowed only for ocean freight and insurance under C.I.F. terms, not for smelting and refining charges.
• Surcharge Liability (ACMDC): ACMDC argued it should not pay the 25% surcharge for late payment on silver, gold, and pyrite because the exact quantities could only be determined after smelting/refining (for silver/gold) and after flotation (for pyrite), and that pyrite was not "removed" from the mine site as it was delivered to a sister company within the concession.
• Manufacturer's Tax (ACMDC): ACMDC contended it was not engaged in the business of selling grinding steel balls, as it only lent them to other companies in isolated transactions as an accommodation.
• Contractor's Tax (ACMDC): ACMDC claimed it did not realize profit from leasing its personal properties, as income only covered operational costs.

• Ad Valorem Tax Base (ACMDC): ACMDC maintained that since copper wire bars are manufactured products, the LME price must be adjusted by deducting smelting and refining charges to approximate the value of the raw copper concentrate at extraction.
• Surcharge Liability (Commissioner): The Commissioner argued that bad faith is not required for the 25% surcharge, and ACMDC could have estimated the quantities of silver, gold, and pyrite via assay reports and paid provisionally.
• Manufacturer's Tax (Commissioner): The Commissioner asserted that ACMDC's sales of grinding steel balls, even if isolated, constituted engaging in business subject to tax.
• Contractor's Tax (Commissioner): The Commissioner contended that ACMDC's series of lease transactions for its plane, motorboat, and dump truck, with reported rental income, proved it was engaged in a leasing business subject to contractor's tax.

• Ad Valorem Tax Computation: Whether smelting and refining charges should be deducted from the London Metal Exchange price of copper wire bars to determine the actual market value of copper concentrates for ad valorem tax purposes.
• Surcharge on Silver, Gold, and Pyrite: Whether ACMDC is liable for a 25% surcharge for late payment of ad valorem taxes on silver, gold, and pyrite extracted in 1976.
• Manufacturer's Sales Tax: Whether ACMDC is liable for manufacturer's sales tax on its sales of grinding steel balls to other mining companies in 1975.
• Contractor's Tax: Whether ACMDC is liable for contractor's tax on income from leasing its personal properties (plane, motorboat, dump truck) in 1975 and 1976.

• Ad Valorem Tax Computation: The deduction of smelting and refining charges is proper. The ad valorem tax is a severance tax based on the mineral's value at extraction. Since copper concentrate has no quoted market price, the LME price of the manufactured wire bar may be used as a reference, but all costs of processing after extraction (smelting, refining, fabricating) must be deducted to approximate the value of the raw concentrate at the mine site.
• Surcharge on Silver, Gold, and Pyrite: ACMDC is liable for the 25% surcharge. The law imposes the surcharge for late payment regardless of bad faith. ACMDC could have determined the estimated quantities of silver and gold via assay reports and paid provisionally. Its claim that pyrite was not "removed" is barred by estoppel, as it had previously declared and paid ad valorem tax on pyrite, and evidence showed shipments outside the mine site.
• Manufacturer's Sales Tax: ACMDC is not liable. To be subject to manufacturer's sales tax, one must be "engaged" in the business of selling. ACMDC's sales of grinding steel balls were isolated transactions undertaken as an accommodation, not with the intent to carry on a business for profit. The activity was incidental to its principal mining business.
• Contractor's Tax: ACMDC is liable. The series of lease transactions, reported rental income over two years, and apparent intention to profit demonstrate that ACMDC was habitually engaged in leasing personal property, subject to the contractor's tax. Its claim of no profit was unsupported by evidence.

• Ad Valorem Tax as a Severance Tax — The ad valorem tax is a charge upon the privilege of severing or extracting minerals from the earth. It is computed based on the actual market value of the mineral in its condition at the time of removal from the mine, before undergoing substantial chemical or manufacturing change. If the manufactured product's price is used as a reference, all processing costs post-extraction must be deducted to approximate the raw mineral's value.
• Engaging in Business for Privilege Tax Purposes — To be liable for a privilege tax (e.g., manufacturer's or contractor's tax), the taxpayer must be "engaged" in the business, which connotes continuity, progression, or sustained activity aimed at profit or livelihood. An isolated transaction, without intent to carry on a business, does not constitute "engaging in business."

• "The ad valorem tax is a tax not on the minerals, but upon the privilege of severing or extracting the same from the earth, the government's right to exact the said impost springing from the Regalian theory of State ownership of its natural resources." — This passage defines the fundamental nature of the ad valorem tax as a severance tax.
• "To be held liable for the payment of a privilege tax, the person or entity must be engaged in business... 'To engage' is to embark on a business or to employ oneself therein. The word 'engaged' connotes more than a single act or a single transaction; it involves some continuity of action." — This excerpt establishes the standard for determining liability for privilege taxes on business.

• Cebu Portland Cement Co. vs. Commissioner of Internal Revenue, L-18649, February 27, 1965, 13 SCRA 333 — Controlling precedent that the ad valorem tax is based on the market value of the mineral in its condition at extraction, not on the manufactured product. The Court applied this principle to hold that cement, having undergone chemical change, is not the "mineral product" contemplated for tax computation.
• Republic Cement Corporation vs. Commissioner of Internal Revenue, L-20660, June 13, 1968, 23 SCRA 967 — Followed and affirmed the principle from Cebu Portland Cement regarding the tax base for ad valorem tax.
• Hilado vs. Collector of Internal Revenue, 100 Phil. 288 (1956) — Distinguished. The Commissioner's reliance on this case (that a current Commissioner is not bound by a predecessor's ruling) was rejected because the prior ruling in question was a decision of the Court of Tax Appeals, a judicial body, not merely an administrative ruling.

• Section 243, National Internal Revenue Code — Imposes an ad valorem tax on the actual market value of the annual gross output of minerals extracted from lands not covered by lease.
• Section 246, National Internal Revenue Code — Defines "gross output" as the actual market value of minerals without deduction for expenses, except for ocean freight and insurance if sold abroad under C.I.F. terms. This provision was central to the dispute over allowable deductions.
• Section 245, National Internal Revenue Code — Provides for the time and manner of payment of ad valorem taxes and imposes a 25% surcharge for late payment. This was the basis for the surcharge liability.
• Section 186, National Internal Revenue Code — Imposes a percentage tax on manufacturers on sales of articles. The definition of "manufacturer" in Section 194(x) was applied to determine ACMDC's liability.
• Section 191, National Internal Revenue Code — Imposes a contractor's tax on, among others, lessors of personal property. This was the basis for the tax on ACMDC's leasing income.

Chief Justice Narvasa, Justice Bidin, Justice Puno, and Justice Mendoza concurred.