Marlborough, MA Office

Mariner serves a broad mix of clients — individuals (including high‑net‑worth households), pension and profit‑sharing plans, trusts, estates, charitable organizations, corporations and private funds — through investment management, financial planning and reporting, retirement plan consulting, and access to pooled vehicles and third‑party managers. The firm also offers coordinated tax services, Core Family Office (CFO) services and employer financial‑wellness tools in addition to traditional portfolio management.

The firm generally implements discretionary, customized portfolios overseen by an Investment Committee and supported by an internal portfolio management team, combining in‑house research with allocations to third‑party managers and platforms (including CAIS access and SEI sub‑advised models). Its strategies span equity and fixed income mandates as well as alternatives, structured notes, options, direct indexing and digital assets, and it provides ERISA 3(38) retirement plan solutions such as the Pathway DC program.

What is less common for a firm of this enterprise scale is the depth of tax and accounting integration: Mariner maintains CPAs and enrolled agents, provides stand‑alone and coordinated tax compliance, planning and preparation, and is affiliated with a specialty tax services entity. The brochure also highlights administrative CFO capabilities (including bill payment and platform administrator authority) and a Financial Wellness Platform for employer clients — operational offerings that are relatively atypical among large advisory enterprises.