Top Investment Underwriting and Family Office Advisors in New York, NY

Wealth and asset management firm headquartered at 1330 Avenue of the Americas in Manhattan, managing $24.7 billion in discretionary assets as of June 30, 2026 for families, endowments, foundations and institutional investors, with a 98% client retention rate; its own site states it was "founded 24 years ago." Its institutional advisory team provides independent, investment-driven due diligence, risk analytics and custom portfolio advisory support, while its alternatives group runs manager due diligence across private equity, venture capital, hedge fund and real estate strategies for client families and institutions.

SitusAMC describes itself as the leading provider of commercial real estate underwriting, diligence and investment advisory, headquartered at 250 West 57th Street in Manhattan. Its underwriting and diligence practice covers debt and equity underwriting, multifamily and agency underwriting, loan sizing, financial diligence, lease audits, site inspections, post-closing modifications and quarterly asset surveillance across all CRE asset classes for lenders and investors. The firm states it supported $29.8 billion in new loan originations in 2025.

BBR Partners is a fee-only multi-family office headquartered at 55 East 52nd Street in Manhattan, founded in 2000 to give wealthy families and entrepreneurs an independent, open-architecture alternative to proprietary asset management, with a typical client minimum of approximately $50 million. Its manager selection process evaluates more than 20,000 managers in its investment universe, applying intensive due diligence and constant monitoring across public equities, fixed income, private equity, venture capital, hedge funds and real estate, alongside wealth advisory and portfolio administration.

AlTi Global, formed from the Tiedemann and Alvarium merger, keeps a Manhattan office at 22 Vanderbilt Avenue and describes itself as offering integrated wealth and investment services to families, family offices, fiduciaries and endowments. Its team of more than 50 investment specialists gives clients institutional-grade access to closed-door direct and co-investment opportunities, including the ability to invest alongside Allianz, one of the largest private markets allocators. The firm states it has $520 million of its own capital invested alongside client capital.

Kroll, headquartered at One World Trade Center in Manhattan, dates its founding to 1932 as Duff & Phelps and now operates as Kroll with roughly 6,500 experts across more than 30 countries. Its Real Estate Advisory Group provides valuation, transaction advisory and due diligence for institutional investors, lenders, and public and private companies, including buy-side and sell-side M&A advisory, RICS appraisals, portfolio valuations, investment feasibility assessments and fairness opinions across the commercial real estate lifecycle.

EisnerAmper, a professional services firm reporting more than 4,500 professionals, states on its own site that it was founded in New York and keeps its headquarters at 733 Third Avenue in Manhattan. Its Transaction Advisory Services practice runs buy-side and sell-side financial, tax and IT due diligence for private equity investors, strategic acquirers, lenders and family-owned businesses, preparing Quality of Earnings analyses that validate EBITDA adjustments and flag deal risks and opportunities ahead of a transaction.

Withum, founded in 1974 and now reporting 3,200 team members and more than 450 partners and principals across 30 offices, maintains a New York City office at 1411 Broadway near Times Square. Its Transaction Advisory Services practice performs buy-side and sell-side due diligence for private equity firms and strategic and credit investors, examining normalized earnings, working capital needs and deal risks, with access to HLB International's global network for cross-border transactions.

Riveron, founded in 2006 and reporting 1,200+ professionals across 18 international offices, maintains a New York office at 10 Grand Central, 155 East 44th Street. Its buy-side diligence practice combines financial, tax, IT and operational review to validate an investment thesis before close, its carve-outs practice supports divestiture separation and TSA management, and its lender services group provides independent due diligence, collateral analysis and portfolio monitoring for private credit decisions.