Manila's Windfall Tax Is Now Live — and the FTAA Carve-Out Has a Supreme Court Asterisk

What happened

Republic Act No. 12253 — the Enhanced Fiscal Regime for Large-Scale Metallic Mining Act — was signed into law by President Ferdinand Marcos Jr. on 4 September 2025 and became operative on 17 February 2026, 150 days after publication in the Official Gazette. The Implementing Rules and Regulations (IRR), issued by the Department of Finance, took effect on 20 December 2025. Seven months into the regime, the first quarterly royalty returns covering the February–June 2026 period are now due for filing, and the windfall profits tax is being computed in earnest for the first time.

The law fundamentally restructures how the Philippine state captures mining revenue. Outside mineral reservations, the fixed royalty is replaced by a five-tier, margin-based sliding scale ranging from 1 percent to 5 percent of income from metallic mining operations, with a 0.1 percent minimum royalty imposed even on loss-making projects. A separate five-tier windfall profits tax — starting at 1 percent and escalating to 10 percent — applies once project margins breach 30 percent, reaching its ceiling at a 75 percent margin. The law also introduces mandatory per-project ring-fencing: each Mineral Production Sharing Agreement (MPSA) or Financial and Technical Assistance Agreement (FTAA) is taxed as a separate legal entity, and losses from one project may not be consolidated against profits from another. A 2:1 debt-to-equity thin capitalisation cap on related-party borrowing limits the deductibility of intra-group financing costs. The Department of Finance projects incremental revenues of ₱25.08 billion between 2026 and 2029, averaging ₱6.26 billion annually.

Critically, the IRR contains a carve-out for FTAAs executed before the law's effectivity: those contracts 'shall not be subject to the taxes imposed under Section 15L-A of the National Internal Revenue Code, as amended by RA 12253, except as may be otherwise determined by the Supreme Court.' This formulation means that the tax immunity of legacy FTAAs is not statutory — it is conditional on the absence of a contrary Supreme Court ruling. Pre-existing MPSAs and FTAAs will continue to be governed by their existing terms unless those agreements themselves provide for the automatic incorporation of future laws, but operators relying on contractual stability will need to watch for any constitutional or tax challenge that could reach the highest court.

Why it matters for dispute formation

The ring-fencing rule is the most immediate commercial pressure point. A company operating, say, three nickel MPSA blocks — one highly profitable, one breakeven, one in temporary curtailment — can no longer use the curtailed block's losses as a shield against windfall profits tax on the profitable block. Each agreement is registered under a distinct branch taxpayer identification number, making the tax footprint of any multi-permit operator significantly larger than legacy financial models assumed. For projects financed on a portfolio basis — where consolidated cash flows underpin debt covenants — the ring-fencing rule may constitute a material change in the underlying economic assumptions, potentially triggering discussions with lenders and, in extreme cases, force-majeure or material-adverse-change provisions.

The FTAA carve-out with its Supreme Court asterisk is the longer-fuse dispute risk. The Philippines has a well-documented history of constitutional challenges to FTAA arrangements: the Supreme Court's 2004 decision in La Bugal-B'laan Tribal Association v. Ramos upheld FTAA validity under the constitution only after years of litigation, and the 2012 Narra Nickel ruling introduced the 'grandfather rule' on foreign equity that retroactively threatened multiple FTAAs. The IRR's formulation that FTAAs are exempt from the windfall profits tax 'except as may be otherwise determined by the Supreme Court' effectively embeds a future-litigation gateway into the statute. Any civil-society group or competitor that successfully petitions the court to extend the windfall profits tax to FTAAs would immediately reopen the tax modelling of every legacy FTAA holder — without any legislative action being required.

From an investment-treaty perspective, foreign investors in the Philippines have recourse under a modest network of bilateral investment treaties, most of which guarantee fair and equitable treatment and protection against uncompensated indirect expropriation. A retroactive judicial extension of the windfall profits tax to FTAAs — particularly where the investor entered relying on the IRR carve-out — would present a textbook legitimate-expectations claim. The thin capitalisation rule also directly constrains how multinational mining groups fund Philippine operations through related-party debt, a common structural tool in the sector. If the rule is applied to existing loan arrangements that predate the IRR, it could trigger disputes over whether the unilateral alteration of deductibility terms constitutes a breach of stabilisation clauses incorporated in older mineral agreements.

The transparency and public-disclosure provisions of RA 12253 add a further dimension: the law mandates public disclosure of beneficial ownership records, tax and non-tax payments, and company filings. For operators whose Philippine structures involve tiered offshore holding companies — a feature common in FTAA arrangements where up to 100 percent foreign ownership is permitted — mandatory disclosure may surface ownership chains that could become the basis for fresh scrutiny under the Narra Nickel grandfather rule or the Anti-Dummy Law.

Who's exposed

What to watch

• Filing and audit of first-quarter royalty returns under RA 12253, covering February–June 2026: any BIR assessment disputing a company's margin computation or ring-fencing classification will be the first live test of the new regime's enforcement mechanics.
• Supreme Court docket for constitutional or tax challenges seeking to extend the windfall profits tax to pre-existing FTAAs — the IRR's carve-out language explicitly preserves this pathway and civil-society groups have a track record of using it.
• Whether the Tampakan copper-gold FTAA restart negotiations incorporate the new fiscal regime into revised project economics, or whether the parties attempt to contractually ring-fence the project inside the legacy FTAA framework.
• Commodity-price sensitivity: with nickel prices having rallied from USD 14,200 to USD 18,700 per tonne between December 2025 and January 2026, a sustained price above USD 17,000 could push multiple laterite operations through the 30 percent margin threshold, triggering the windfall profits tax for the first time in the second-half 2026 returns.