Marianne Voss is a seasoned governance and an ESG leader with over two decades of experience at the intersection of business, law, finance, and sustainability.  Based in Stonington, Connecticut, Marianne is widely recognized for her ability to translate complex environmental, social, and regulatory challenges into strategic opportunities that enhance enterprise value and build long-term resilience.

Currently serving as Managing Director and Chief ESG Officer at Webster Equity Partners, Marianne oversees the firm’s $9 billion AUM ESG strategy and serves on the Investment Committee. She has built and institutionalized a firm-wide ESG infrastructure — surpassing industry benchmarks in under two years, increasing ESG-motivated allocations by 45%, and embedding analytics, risk modeling, and regulatory compliance (e.g., SFDR, TCFD) across deal flow and portfolio governance. She advises boards and executive teams on effective governance, sustainable value creation, enterprise risk and stakeholder engagement.

Marianne brings a strong track record of advisory experience across private equity, corporate, development, finance, and nonprofits. Her insights have shaped strategy for dozens of boards and executive teams navigating sustainability, regulatory and reputational risk— as well as emerging issues like GenAI adoption, workforce health, and responsible sourcing.

Previously, Marianne was the founder and principal of Ethos Matters, an ESG advisory firm. Earlier in her career, Marianne held senior sustainability roles at Adidas, Reebok, and Oxfam America. During her tenure, she has led ESG due diligence, post-M&A integration, and global policy advocacy.  She helped drive a 35% average improvement in ESG ratings across 60+ investment deals. Marianne has also launched and led multistakeholder initiatives addressing labor protections in U.S. supply chains —  Stronger Together US and the Ethical Charter  — demonstrating her deep credibility on labor rights, ethical governance, and system-level collaboration.  Her policy expertise and stakeholder diplomacy helped shape standards adopted across deforestation-linked supply chains and contributed to the development of globally recognized sustainability benchmarks such as the Accountability Framework and Cradle to Cradle certification programs.

Marianne is a firm believer in the power of practical, elegant strategies to solve complex challenges. Her leadership style is grounded in collaboration, transparency, and trust-building — particularly in environments where skepticism must be met with results. Known for mentoring rising ESG talent and cultivating high-performing teams, she is also an advocate for continuous learning and cross-sector dialogue.

Marianne holds a JD from Boston University School of Law and a MALD from The Fletcher School at Tufts University, with concentrations in international law and human rights. She is an experienced public speaker, adjunct professor, and trusted voice on governance, sustainability, and innovation. 

Marianne brings to boards a disciplined, collaborative, and forward-thinking perspective — with deep expertise in ESG strategy, risk oversight, stakeholder trust, and sustainable growth. Her leadership is especially valuable to companies navigating change, scaling impact, or seeking to align fiduciary duty with long-term stakeholder value.

Character
Marianne Voss is a principled and purpose-driven leader who consistently demonstrates integrity, compassion, and resilience in advancing ESG initiatives that create real-world impact. She is deeply committed to ethical leadership, building trust across diverse stakeholders, and aligning sustainability values with actionable business goals.

Knowledge
With a dual background in law and international public policy, and real-world application in public and private sectors, Marianne brings extensive expertise in regulatory compliance, sustainable finance, ESG analytics, and human rights. Her mastery of global disclosure frameworks and evolving sustainability standards positions her as a thought leader across private equity, corporate, and nonprofit sectors.

Strategic
Marianne excels at designing and executing high-impact ESG strategies that drive long-term value, manage risk, and enhance operational performance. She has successfully built multiple firm-wide ESG programs, guided post-M&A integrations, and advised Fortune 500 companies on aligning sustainability with corporate growth objectives.

Communication
An articulate and persuasive communicator, Marianne engages boards, investors, and stakeholders with clarity and purpose, translating complex ESG topics into compelling narratives and practical solutions. Her collaborative approach fosters alignment, empowers teams, and drives progress in even the most challenging environments.