Patrick W Pearsall is the chair of Jenner & Block’s public international law practice. He has extensive experience in representing parties in complex commercial arbitration and investment disputes. Mr Pearsall served in the US State Department from 2009 to 2017 and was the Chief of Investment Arbitration from 2015 onwards. He has arbitrated claims involving billions of dollars on behalf of the United States, other sovereign states, and private investors in both commercial arbitration and investment arbitration. He is a trusted adviser to governments and private entities, and is regularly called upon to provide strategic counsel before a dispute arises. In addition to his representations, he has advised on the revision of the International Court of Arbitration’s rules, and led the negotiations of several bilateral and multilateral treaties. Most recently, he advised on the negotiation of the investment provisions in the Trans-Pacific Partnership, the Transatlantic Trade and Investment Partnership and the US–China Bilateral Investment Treaty.