* Serve as the lead tax advisor and primary point of accountability for a select group of Regis families, maintaining and growing a book of clients with balance sheets that often exceed +$100M. * Build practical, year-round, and multi-year tax strategies tailored to each family’s goals, ownership structures, businesses, trusts, investments, charitable activities, and succession plans. * Lead and develop a select team of UHNW-focused tax professionals supporting Regis engagements, overseeing staffing, engagement economics, billing, and service quality. * Identify planning opportunities and risks arising from business transactions, concentrated positions, real estate, carried interests, equity compensation, major charitable gifts, residency changes, and cross-border exposure (foreign trusts, PFICs, GILTI, FATCA/FBAR) bringing in specialists when the issue calls for deeper expertise. * Oversee tax compliance at a level appropriate to each engagement: directly, when Mercer prepares the returns, or through active review and coordination when a family’s own CPA firm or internal tax team handles preparation. * Lead the response to significant federal and state tax notices, examinations, and controversy matters, coordinating with counsel and other specialists through resolution. * Partners with Regis wealth advisors and Mercer’s broader team — estate planning, investments, financial planning, and family office services — so tax advice is fully integrated with each family’s overall plan. * When relevant, collaborate and coordinate the tax calendar / division of responsibilities with the families outside CPAs, attorneys, trustees, investment bankers, valuation professionals, controllers, and other advisors * Support new client development through prospective client meetings and partner with Regis leadership to evolve the tax service model, team, and technology.