About Tidemark
Tidemark partners with mission-driven institutions, foundations, and leaders to design philanthropic impact that endures. Grounded in strategy and narrative clarity, we help organizations align purpose with performance, translating aspiration into measurable impact.
Philanthropy, at its best, is both vision and structure: the meeting point of generosity and discipline. We work with change-makers who believe in doing good with precision, where legacy is an architecture.
Why We Exist
The word tidemark describes the visible line left when the tide has reached its highest point. We exist to help institutions reach, and define, theirs.
Tidemark was founded on the belief that precision, courage, and purpose can transform institutions.
We partner with schools, foundations, and mission-driven organizations to design advancement strategies rooted in trust and long-term impact. Our work helps leaders rise above complexity and navigate moments of change with steadiness and vision.
About the Founder
Erika McMahon is a nationally recognized advancement strategist and advisor whose career has been dedicated to helping mission-driven institutions raise transformational support and build enduring cultures of philanthropy.
Over the past two decades, she has led schools, universities, and foundations through record-setting campaigns and periods of significant organizational change—unifying boards, leaders, and donors around a shared vision of impact.
Before founding Tidemark Philanthropy, Erika served as Chief Advancement Officer at The Winsor School and Notre Dame Academy as well as leadership positions at Simmons University, guiding advancement strategies across two $100M campaigns and overseeing comprehensive fundraising, engagement, and communications programs.
Her expertise in women’s philanthropy and leadership alignment informs a distinctive, values-based approach to institutional advancement; where trust, transparency, and disciplined strategy drive results.
A published writer and speaker, Erika’s work explores the future of fundraising and the cultural shifts shaping women’s giving and educational leadership. Her op-eds have appeared in The Boston Globe, Boston.com, and WBUR Cognoscenti, and she has presented at national conferences including CASE-NAIS, NEDRA, and other gatherings focused on philanthropy and social impact.
Erika brings both strategic precision and deep relational insight to her work; helping institutions meet ambitious goals and redefine what’s possible when mission and momentum align.
