Global Insight. Regional Expertise. Legal Strategy. Across the Americas.
We don’t just speak the language of the Americas. we understand the people, the subtleties, and how better business is done
A B O U T U S
Strategic Counsel for a Connected Hemisphere
Sánchez Thomas is a strategic legal and government affairs advisory firm focused on the Americas. Based in Washington, D.C., we combine deep regional insight with decades of experience across the United States, Latin America, and the Caribbean. We advise global businesses, international organizations, and sovereign clients on strategic legal matters, regulatory strategy, and cross-border transactions.
Barranquilla, Colombia
Our work sits at the intersection of law, public policy, technology, and investment—leveraging innovations such as artificial intelligence to deliver forward-looking solutions that bridge jurisdictions and unlock opportunities across borders.
M I S S I O N
Our mission is to turn legal complexity into strategic clarity—across borders, sectors, and systems of power.
S E R V I C E S
Where Law and Policy align with Strategy
We connect capital, institutions, and public power through sound legal strategy and regional fluency. From cross-border transactions to regulatory compliance, we provide the legal direction that drives results across the Americas.
PRACTICE AREAS
TRANSACTIONS, INVESTMENT AND COMPLIANCE
From market entry to complex regulation, we help clients anticipate challenges, seize opportunities, and manage corruption risks across the Americas.
We negotiate agreements that protect our clients’ interests while enabling efficient execution, and we guide them in preventing, detecting, and addressing corruption risks across jurisdictions.
The result: investments and transactions that move forward with confidence, integrity, and strategic advantage.
GOVERNMENT AFFAIRS & REGULATORY STRATEGY
We help clients navigate the intersection of law, policy, and power. With deep insight into U.S., Latin American, and Caribbean political landscapes, we provide forward-looking counsel on regulatory change, legislative momentum, and strategic stakeholder engagement.
From advancing business goals to anticipating policy shifts or protecting hard-earned reputations, we craft agile public affairs strategies that align legal goals with government realities—locally, regionally, and globally
STRATEGIC DISPUTE RESOLUTION
We represent clients in complex disputes that cross borders, industries, and jurisdictions.
Our team leverages trusted tools—international arbitration, mediation, and cross-border litigation—to resolve disputes efficiently and strategically.
Where litigation is unavoidable, we coordinate proceedings across jurisdictions with precision and global perspective, ensuring that our clients’ interests are protected at every stage.
CLIENTS
Private Investors and Corporations
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Our clients are global businesses and investors expanding into—and doing business across—the Americas. They operate in fast-moving markets where regulation, politics, and cross-border risks intersect. We provide the strategy and insight they need to seize opportunities with confidence and protect their interests across jurisdictions.
Government Clients
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We support sovereign states in designing and negotiating investment frameworks that foster sustainable growth while safeguarding national interests. Our services include treaty and legal analysis, risk assessments, and drafting support to strengthen negotiation capacity and align with international standards. Whether updating bilateral investment treaties or developing new strategies to attract responsible investment, we provide legal and policy guidance grounded in regional expertise and global best practices.
Development Finance Institutions (DFIs) / Multilaterals (MDBs).
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We serve international organizations and development institutions advancing sustainable growth across the Americas. We provide legal and policy support that strengthens investment protections, builds institutional capacity, and enhances negotiation strategies. Our services include due diligence, compliance, and risk assessments for public, private, and PPP projects—ensuring development goals are pursued responsibly while protecting long-term interests.
P E O P L E
Sánchez Thomas was founded to meet the legal and policy challenges of a global, multilingual world—and now returns with a sharper, more focused mission. Formerly operating as Disán, the firm has reopened with expanded services to provide high-level legal strategy, government relations, and cross-border counsel rooted in decades of experience in the Americas and beyond.
Our work is led by founder Margarita R. Sánchez and supported by a trusted network of professionals—including lawyers, engineers, economists, policymakers, and academics—who bring multidisciplinary insight to every engagement.
Margarita R. Sánchez
FOUNDER AND MANAGING PARTNER
Margarita Rosa Sánchez is an international lawyer and arbitrator with more than 25 years of experience representing public and private clients in litigation, arbitration, and anti-corruption matters across the Americas, Europe, Asia, and the Middle East. She has represented sovereign states, corporations, and individuals in complex high-profile disputes and investigations, including international arbitrations under ICSID, ICC, ICDR, FINRA, and other institutional rules. Her white-collar work includes leading investigations under the Foreign Corrupt Practices Act (FCPA), multilateral development banks and international organizations (IDB, World Bank, Caribbean Development Bank, United Nations). She has received consistent international recognition as a leading lawyer in international arbitration and white-collar crime by major rankings and publications, including Chambers, Legal 500, and Latinvex.
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Margarita R. Sánchez is the founding partner of Sánchez Thomas, a strategic advisory firm focused on cross-border legal and government affairs throughout the Americas. Prior to founding the firm, she practiced at leading international law firms in Washington, D.C., representing sovereign states, multinational corporations, and individuals in complex disputes and investigations.
Earlier in her career, she served in the Office of Institutional Integrity of the Inter-American Development Bank, where she investigated allegations of fraud and corruption and contributed to the development of the Bank’s first sanctions procedures. She also played a role in the creation of the Uniform Framework for Preventing and Combating Fraud and Corruption, adopted in 2006 by major multilateral development banks and the International Monetary Fund. She began her legal career at Monómeros Colombo Venezolanos S.A., a fertilizer and chemical company, where she oversaw compliance with Colombia’s anti-drug and anti-money laundering regulations.
The founding of Sánchez Thomas reflects her vision of building a firm that integrates deep regional expertise, a multidisciplinary approach, and technology driven solutions to address increasingly complex client needs.
Her commitment to public service includes serving as Co Vice Chair of the International Bar Association Access to Justice and Legal Aid Committee, Commissioner of the Hispanic National Bar Association Latina Commission, and member of the D.C. Bar Inter American Legal Affairs Subcommittee.
Margarita served as Adjunct Professor at Georgetown University from 2014 - 2016 and has lectured at the International Law Institute since 2013. In 2015, she was elected a Fellow of the Chartered Institute of Arbitrators in London. She has published on international arbitration and corruption in leading academic and professional publications and is the author of a chapter on corruption in international arbitration in a volume published by Editorial Ibáñez in 2019.
She earned her Juris Doctor and a graduate certificate in Economic and Political Studies from Universidad del Norte, and an LL.M. in Law and Government from American University. She is currently pursuing a Ph.D. in Law at the University of Seville, focusing on the historical and philosophical foundations of access to justice and human dignity.
Margarita is a practicing trial attorney in the District of Columbia, admitted before the U.S. Supreme Court and the U.S. Court of Appeals for the D.C. Circuit, and is also admitted to practice in Colombia.
Marcela Duque Penagos
PARTNER
Marcela Duque Penagos is a Colombian international lawyer based in Mexico City. Over the past decade, she has focused on integrity, anti-corruption, and AML/CFT compliance matters across Latin America, with a deep focus on Multilateral Development Banks (MDBs) and International Organizations projects and operations. Her work with MDBs includes participating in investigations of Prohibited Practices, advising Latin American countries and private companies on implementing international anti-corruption and AML standards, conducting regulatory diagnostics, advising on reforms for public integrity frameworks, and guiding the modernization of state institutions in the Region. Marcela has represented governments, corporations, and individuals in MDBs sanctions proceedings, international arbitration, and FCPA investigations.
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Marcela and Margarita have been trusted allies since the early days at Disan LLP, building a collaboration that spans more than a decade. . Today, their partnership at Sánchez Thomas carries that spirit forward bringing together deep regional expertise, a multidisciplinary approach, and technology-driven solutions to transform legal complexity into strategic clarity, across borders, sectors, and systems of power.
Since 2019, Marcela has worked with MDBs in several capacities: participating in investigations of Prohibited Practices, advising Latin American countries on implementing international standards on anti-corruption and AML—conducting regulatory diagnostics, advising on reforms for public integrity frameworks, supervising the implementation of anti-corruption measures in the public sector and guiding the modernization of state institutions in the region.
Before joining the MDB ecosystem, Marcela worked at DISAN LLP as an International Counsel. There, she represented sovereign states and corporations in investment arbitration disputes under international treaties and public international law. She also represented clients in MDB sanctions proceedings, designed Business and Human Rights compliance programs based on UN Guiding Principles, and advised foreign investors on navigating Latin American public procurement processes.
Earlier in her career, Marcela worked at Colombia's Ministry of Justice and Law in the Criminal Policy Division. She helped design transitional justice mechanisms, worked with Congress on Criminal Code reforms, and contributed to Colombia's implementation of the OECD Anti-Bribery Convention. She also assessed human rights conditions in prisons across the country, with special attention to female prisoners, and developed strategies to address violations.
Marcela's commitment to public service extends beyond her legal practice. At the Inter-American Commission on Human Rights, she reviewed petitions involving criminal due process, personal integrity, and privacy rights under the American Convention on Human Rights. In Arusha, Tanzania, she volunteered to fundraise for and help build a school, developed educational programs for local children, and designed a microfinance initiative for women—a program that continues to empower the community today. She has also contributed to research at the Columbia Center for Investment, examining social responsibility practices and voluntary initiatives in the global mining sector.
Marcela earned her J.D. from Universidad de los Andes in Colombia and her LL.M., with honors, from Columbia University.
E. Rainbow Willard
PARTNER
E. Rainbow Willard is an international counsel and independent arbitrator in international commercial and investment arbitrations and related federal litigation. Over the course of fifteen years, Rainbow has acted in complex, high-stakes international arbitrations under all major rules, including UNCITRAL, ICC, ICSID, SIAC, and LCIA, with claims totalling more than USD $50 billion. She has been recognized as a Rising Star by Legal 500 and an Up-and-Coming Practitioner by Chambers USA. Prior to forming her practice, Rainbow was Counsel at leading disputes boutique Chaffetz Lindsey LLP in New York and was a Senior Associate at Allen & Overy LLP, practicing in London and New York. Specializing in commercial and investment disputes involving large-scale energy projects, she has handled matters relating to solar, wind, coal, gas, and hydroelectric power plants.
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Her background also includes matters arising in the oil & gas, mining, telecommunications, and construction sectors across North America, Latin America, the Caribbean, South Asia, the Middle East, and Europe. She regularly handles complex matters that include parallel proceedings in multiple jurisdictions.
Rainbow has acted as first- and second-chair counsel in international commercial and investment arbitrations seated around the world. She also honed her oral advocacy skills as a federal public defender in Miami, where she acted as lead defense counsel in more than 100 federal felony cases, handling matters before federal judges and juries from inception through trial and appeal.
With more than twenty-five years of experience studying and working throughout Latin America, she has handled commercial arbitrations arising from transactions in several jurisdictions, including Ecuador, Argentina, Peru, Chile, and Mexico and has represented States and investors in treaty arbitrations across the region. Rainbow studied civil law in Mexico at the Universidad Panamericana. Prior to becoming a lawyer, Rainbow lived in Guatemala, where she advised on indigenous language development projects.
She brings extensive international and domestic criminal law experience gained during three terms of government service and regularly handles international arbitration matters involving allegations of corruption, fraud, or money laundering. Most recently, at the US Department of Justice, Rainbow assisted more than twenty governments in North America, Central America, and the Caribbean with their cross-border criminal investigations, developing familiarity with how different States collect criminal evidence and structure prosecutions.
Fully fluent in Spanish, she has served as party representative in high-stakes disputes conducted entirely in Spanish, delivering substantial oral advocacy and drafting all written submissions. Rainbow speaks regularly at Spanish-language international arbitration events and previously represented the US government in official meetings and communications in Spanish.
Having served as sole and co-arbitrator in UK and US-seated contractual disputes, she is a Fellow of the Chartered Institute of Arbitrators, a member of the AAA-ICDR (international) and AAA Commercial (domestic) Panels of Arbitrators, and a certified mediator.
Natalia Giraldo Carrillo
OF COUNSEL
Natalia Giraldo Carrillo is an accomplished international arbitration lawyer with over 18 years of experience representing sovereign States and private entities in complex, high-stakes cross-border disputes. Her practice focuses on investment treaty and commercial arbitration under ICSID, UNCITRAL, and ICC rules, with a specialized emphasis on regulatory compliance and corruption allegations within international investment law. She has participated in over 35 international arbitration matters, representing both claimants and respondents, including sovereign entities on behalf of her native Colombia. Her experience spans diverse sectors such as telecommunications, construction, hydropower and energy projects, ports and transportation, oil and gas, mining, real estate projects, and intellectual property—including trademarks and rights.
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She has advised the Colombian government on legislation concerning submerged cultural heritage to ensure alignment with the principles of the 2001 UNESCO Convention and other instruments of public international law, and was part of the legal team representing Colombia in the landmark U.S. federal litigation concerning the Galeón San José. Natalia also represented a Colombian railroad company (formerly a state entity) in one of the largest international commercial arbitrations in Colombia, and a Latin American State before the International Court of Justice (ICJ) in a high-profile boundary dispute.
After nearly two decades in global law firms in Paris, Washington, D.C., and New York, Natalia now serves as an Of Counsel to Sánchez Thomas, where she provides matter-specific legal and strategic advisory services.
In recognition of her expertise in international law and arbitration, Natalia was profiled by Marquis Who’s Who in September 2025. She has been appointed as an External Member of the Sanctions Committee of the Inter-American Development Bank (IDB) for the 2026–2031 term. In that capacity, she adjudicates complex allegations of prohibited practices to ensure institutional integrity and adherence to internal and international regulatory standards.
She has published articles on international arbitration and corruption in renowned academic and professional publications, contributing to ongoing developments in international investment law.
Beyond her arbitration work, Natalia led a two-year advisory for Kids in Need of Defense (KIND), managing multi-stakeholder governance as the primary legal bridge between sovereign agencies, partner law firms across four countries, and non-profit leadership to ensure program compliance and institutional alignment.
Natalia obtained her law degree (Juris Doctor) with honors from the Pontificia Universidad Javeriana in Colombia. She earned an LL.M. in International Legal Studies (2010) from the New York University School of Law, where she served as Graduate Editor of the Journal of International Law and Politics and as a research assistant to Professor Franco Ferrari. She also holds an LL.M. in French, European, and International Business Law (2007) from the Université Panthéon-Assas (Paris II) – Institut de Droit Comparé.
She is fluent in English, Spanish, and French.
At Sánchez Thomas, we believe that the practice of law is not only about solving problems, but also about creating impact. Transparency drives us, and we put our values into action by ensuring that every dollar of our revenue supports the firm’s three pillars:
DELIVER
– We focus on results, continually improving and applying sound judgment to help our clients succeed.
INNOVATE
– We embrace knowledge and technology, including artificial intelligence, to stay at the forefront of law and policy.
GIVE
– We believe in equal access to justice, proudly funding and supporting pro bono initiatives we care deeply about.
Through these pillars, we provide legal and policy guidance to non-profits, academic institutions, and community initiatives across the Americas —advancing anti-corruption efforts, promoting human rights, and mentoring the next generation of lawyers.
THE BRIEF
The Brief brings together Sánchez Thomas analysis on the issues shaping international legal practice in Latin America: anticorruption, regulatory compliance, sanctions, and arbitration. The region moves fast — we write to help decision-makers keep up.
Stay Ahead
RECEIVE INSIGHTS ON LAW, POLICY, AND STRATEGY SHAPING BUSINESS ACROSS THE REGION.