Mark Tassie

Mark Tassie is the founder of Longleaf Private Wealth, a boutique advisory firm built for families who value clarity, discipline, and generational stewardship.

For more than two decades, Mark has worked in markets and private wealth, guiding families through the real-world complexities that sit behind portfolios—taxes, concentrated positions, liquidity events, estate plans, business interests, and the emotional side of wealth. His career began on the trading side of Wall Street, where he developed a deep respect for risk, capital markets, and the cost of mistakes. That foundation still shapes how he thinks about money today: thoughtfully, conservatively, and with a long horizon.

Longleaf was created to give clients something different from the traditional advisory experience—a quieter, more intentional relationship with their wealth. Instead of fragmented advice across multiple professionals, Mark acts as a central steward, coordinating investments, tax strategy, estate planning, and risk management into a single, coherent plan. The goal is simple: fewer moving parts, fewer blind spots, and a higher standard of care.

Mark works closely with families who are navigating the responsibilities that come with meaningful wealth—business owners, executives, inheritors, and multigenerational households who want their financial lives to feel organized, deliberate, and aligned with their values. His approach is not driven by products or transactions, but by long-term partnership and thoughtful planning.

The firm’s name reflects that philosophy. The longleaf pine is known for growing slowly, standing firm through storms, and thriving for centuries. That same patience, resilience, and stewardship is what Mark brings to the families he serves.