Investor-State Arbitration

As one of the most experienced and successful firms in the world in investor-state arbitration, Weil has handled many of the highest-value and most complex cases in the field, involving virtually every type of investment arising from almost every corner of the globe, and remains among the very top firms in the field today.
We have successfully represented both investors and states in arbitration arising out of bilateral investment treaties (BITs), multilateral investment treaties (such as NAFTA, CAFTA-DR, and the Energy Charter Treaty), investment agreements, and domestic investment laws.

We combine unparalleled substantive expertise of international investment law with our industry-leading skills in arbitral advocacy, a deep understanding of the political and commercial settings in which these cases arise, and extensive experience in successfully resolving these cases – both by arbitrating them to conclusion and by negotiated settlement.

In addition to having distinguished careers in private practice, a number of our lawyers previously served in high-ranking positions in the United States Government (including in the White House, the State Department, and the Office of the U.S. Trade Representative), where they negotiated some of the most significant investment treaties in the world (including, for example, NAFTA and CAFTA-DR), and represented the United States in major international disputes.

We have handled not only investor-state arbitration cases through award but also ICSID annulment proceedings and other post-award challenges, as well as recognition and enforcement proceedings.

Selected Representations

Recent Investor State Matters


The Czech Republic

Williams Companies’ Venezuelan gas facilities

Republic of Ecuador

Government of Hungary

Ranked among the top 20 law firms in the world for Dispute Resolution by Chambers Global 2016.

This thriving nationwide group continues to flourish in the international arbitration space. The firm is able to draw on its multijurisdictional and multilingual capabilities to tailor its service to each client and specific dispute. It is held in particularly high esteem for its investment treaty practice, and also has a successful commercial practice…Sources say: 'The team has been straightforward, hard-working and diligent. It is as dedicated to the business as I am.'”

Chambers USA

Known for key focus on investor-state arbitrations, in addition to handling commercial matters arising from a variety of sectors, including oil and gas. Clients include governments, contractors and entities with global operations.

Chambers Global

Weil Named Among Top International Arbitration Practices in the U.S.

Legal 500 US

Consistently ranked Tier 1 in "International Arbitration - Governmental" in the U.S.

U.S. News - Best Lawyers "Best Law Firms" Rankings