9REN Holding v. Spain (Brief for the United States as)
ICSID · Investment (ICSID and treaty) · International (investor-state) · May 26, 2026
Why it matters
9REN Holding v. Spain is an investment-treaty arbitration, in which a foreign investor argued that a state had fallen short of the protections it had promised under a treaty. Disputes of this kind turn on the balance between an investor's protections and a state's freedom to regulate in the public interest. The tribunal's full reasoning, and any sum awarded, are set out in the original.
Summary
This is the brief for the united states as amicus curiae before the u.s. supreme court in 9REN Holding v. Spain, handed down on 26 May 2026. It belongs to the world of investment-treaty arbitration, in which a foreign investor brings a claim against a state, saying the state has breached the protections promised to investors under a treaty. The matter was before an investment-treaty tribunal, the usual machinery for disputes of this kind. italaw is the established open archive for this field, and this entry points to its record; the tribunal's full reasoning, and any sum it awarded, are set out in the document itself.
The detail
Parties: 9REN Holding v. Spain
Case number: See italaw record
Outcome: Brief for the United States as Amicus Curiae before the U.S. Supreme Court in 9REN Holding v. Spain. The disposition is set out in the original.
Applicable law: The applicable investment treaty; ICSID, UNCITRAL or ad hoc arbitration rules.
Issues in play: A foreign investor's treaty protections weighed against a sovereign state's exercise of its powers.
Read the full decision at italaw ↗
Locus Standi links to the source decision and publishes its own plain-language summary. It does not reproduce the text of the award.