Declan Tansey | People | Arnold & Porter

Declan Tansey represents tax-exempt organizations and philanthropists in a broad range of transactional, regulatory, and operational matters. He serves as a strategic advisor across the nonprofit sector, helping clients design and implement structures that support complex charitable, scientific, and philanthropic objectives.

Declan counsels tax-exempt organizations on formation, tax-exempt qualification, governance, operations, grantmaking, and regulatory compliance. His clients include private foundations, public charities, social welfare and political organizations, trade associations, academic and medical research institutions, and international NGOs. He advises nonprofits on a wide array of transactional, regulatory, and operational matters, including complex organizational structures; corporate transactions such as mergers and asset transfers; domestic and international grantmaking programs; lobbying and political activity compliance; and international affiliation structures.

He also assists nonprofits in designing hybrid models to advance philanthropic goals, including forming incubators and impact funds, structuring program-related and mission-related investments, and establishing joint ventures, subsidiaries, and affiliates across nonprofit and for-profit entities. In addition, he works with companies on corporate philanthropy initiatives, including corporate giving, corporate foundations, and collaborations with nonprofit partners.

A major focus of Declan’s work is nonprofit medical and scientific research initiatives. He advises funders and research organizations on establishing multi-institutional consortia with universities, hospitals, and other research institutions to support cutting-edge scientific work. His experience includes negotiating complex affiliation agreements, advising on impact-investing vehicles and strategies, and addressing intellectual property management and commercialization issues. Declan has played a key role in structuring and documenting several significant medical venture philanthropy transactions in recent years.

Declan also advises donors on major gifts to universities, hospitals, research institutions, and charities, as well as political and advocacy-related giving to social welfare organizations, campaigns, and PACs. He works with high-net-worth individuals and family offices to design and manage multi-entity philanthropic structures, including structuring complex gifts, coordinating among multiple philanthropic vehicles, and developing governance frameworks to support sustained impact.

In addition, Declan represents nonprofit organizations in governance disputes, internal investigations, and examinations by federal and state regulators, including IRS audits and congressional inquiries. He works closely with boards and executive leadership on governance matters, providing guidance on fiduciary duties, conflicts of interest, executive compensation, oversight, and internal controls in complex organizational contexts.

Focus Areas

Experience

Multiple tax-exempt organizations — including private foundations, operating charities, and social welfare organizations — on maintaining tax-exempt status and managing governance, operations, and grantmaking.
Multiple family offices in structuring, managing, and operating philanthropic and policy vehicles, including individual charitable giving; supported tax-exempt organizations (such as private foundations, donor-advised funds, and 501(c)(4) advocacy organizations); and for-profit mission-related entities and investments.
Medical and scientific research organizations on formation and ongoing operations, including establishing consortia with major hospitals, universities, and research institutions, as well as developing structures for the management and commercialization of intellectual property.
Multiple private foundations in funding and implementing multi-institutional consortia to advance medical and scientific research.
High-net-worth individuals in negotiating major gifts to universities, hospitals, research institutions, charities, 501(c)(4) advocacy organizations, and PACs.

Multiple tax-exempt organizations in designing and managing operational and grantmaking programs focused on artificial intelligence safety, emerging technologies, global catastrophic risk mitigation, and effective altruism.
Multiple tax-exempt organizations in structuring complex mergers, asset transfers, hybrid structures, and philanthropic investment funds.
Private operating foundation in converting private land into a public park and ecological preserve.
Private operating foundation in structuring and operating an art museum and sculpture park.
National governing body in a governance dispute and related internal investigation, including advising on board authority, fiduciary duties, and organizational compliance.