The arbitral tribunal found Mexico liable for breaching the Minimum Standard of Treatment under NAFTA Article 1105 and awarded USD 15.88 million. The dispute arose out of regulatory and administrative measures adopted by Mexican federal, state, and municipal authorities affecting the limestone quarrying and export operations of Claimant Legacy Vulcan, LLC through its Mexican subsidiary Calizas Industriales del Carmen, S.A. de C.V. (CALICA) in the State of Quintana Roo. Claimant asserted claims under NAFTA Chapter 11 on its own behalf (Article 1116) and on behalf of CALICA (Article 1117), alleging that Mexico violated NAFTA Articles 1105 (Minimum Standard of Treatment) and 1103 (Most-Favored-Nation Treatment). Specifically, Claimant challenged the repudiation and abandonment of agreements executed in 2014 and 2015 to amend the municipal ecological zoning program (POEL 2009) to enable quarrying at the La Adelita lot; the unlawful collection and refusal to reimburse port tariffs at Punta Venado; and the arbitrary shutdown of quarrying operations at El Corchalito in 2018. Claimant subsequently sought leave to introduce an ancillary claim regarding the 2022 shutdown of its La Rosita lot, while Respondent asserted a counterclaim for alleged environmental damage. On jurisdiction and admissibility, the Tribunal confirmed its jurisdiction ratione temporis and ratione materiae over the original claims under NAFTA and Article 25(1) of the ICSID Convention. However, the Tribunal dismissed the port tariff claim on the merits, holding that Mexican court judgments had not ordered reimbursement of the fees. By majority, the Tribunal declined jurisdiction over the ancillary claim concerning La Rosita, determining that Claimant’s pre-1994 investment in La Rosita did not constitute a protected "legacy investment" within the meaning of Annex 14-C of the USMCA. The Tribunal also rejected Respondent's counterclaim as untimely pursuant to ICSID Arbitration Rule 40(2) and inadmissible, observing that the alleged facts and environmental concerns were well known to Respondent prior to the submission of its original Counter-Memorial. Regarding the applicable legal standards, the Tribunal held that it was bound by the NAFTA Free Trade Commission's Note of Interpretation of 31 July 2001, confirming that Article 1105(1) reflects the customary international law minimum standard of treatment as articulated in Waste Management v. Mexico II. The Tribunal rejected Claimant's argument that an autonomous fair and equitable treatment standard or an umbrella clause from third-party treaties could be imported via NAFTA Article 1103 without demonstrating that an actual third-country investor in like circumstances had received more favorable treatment. On liability, the Tribunal concluded that Respondent breached NAFTA Article 1105 with respect to both La Adelita and El Corchalito. In relation to La Adelita, Mexico breached Claimant's legitimate expectations and acted arbitrarily by abruptly abandoning the agreed POEL amendment process without technical or legal justification. In relation to El Corchalito, the Tribunal held that PROFEPA's shutdown order and October 2020 Resolution were arbitrary, disproportionate, lacking in due process, and pretextual, having excluded CALICA's expert surveying evidence and locked the investor into a self-perpetuating catch-22 situation resulting in an indefinite shutdown. On quantum, the Tribunal rejected Claimant's damages model valuing the integrated "CALICA Network" (including Bahamian shipping and US distribution yards), holding that non-Mexican assets were too remote and not legally compensable under NAFTA causation requirements. With respect to La Adelita, damages were denied because Claimant failed to prove that the participatory POEL amendment process would have successfully resulted in quarrying authorizations. For El Corchalito, the Tribunal adopted Respondent’s discounted cash flow model based on transfer pricing, adjusted for a corrected 7.97% discount rate and an additional USD 1.5 million for below-water extraction costs, awarding Claimant USD 15,884,117.00. The Tribunal also awarded pre- and post-award compound interest at the six-month US Treasury bill rate plus 2% from 24 January 2018 until full payment, and ordered each party to bear its own legal fees and half of the arbitration costs (paras. 502-1553).