People

Louis C. Grassi, CPA, CFE, is the Chief Executive Officer of Grassi, a nationally recognized advisory, tax and accounting firm ranked the 52nd largest in the nation and the second-largest employee-owned firm in the profession. Since founding the firm at the age of 24, Lou has led Grassi through 45 years of industry change. In 2023, he spearheaded the firm’s transition to an employee-owned ESOP model, reinforcing a culture of ownership and accountability in an industry increasingly defined by private equity consolidation.

With extensive experience in tax, accounting and consulting, Lou takes a proactive role with clients, providing value-added services such as profit-enhancement studies, operational reviews, performance benchmarking, forensic accounting, cost analysis, incentive compensation programs, estate and succession planning, corporate restructuring and corporate retreat facilitation. Lou’s counsel has proven instrumental to the success of many companies in various industries.

Lou has earned numerous industry accolades throughout his career. In 2025, he was honored as a Long Island Business News ICON. Forbes named him to its inaugural Best-in-State and America’s Top 200 CPAs lists, while Accounting Today recognized him twice as a “Managing Partner Elite” honoree (2014 and 2022). He was also voted “Most Admired” by his CPA peers, as recognized by INSIDE Public Accounting and has been named an “Outstanding CEO” by several New York–area publications.

Under Lou’s leadership, Grassi has garnered client satisfaction rates more than twice the industry average and received the Best of Accounting Award for exemplary client service for five consecutive years. The firm has also been ranked 15 times as a “Best of the Best” firm by INSIDE Public Accounting, recognized by Crain’s New York Business as one of the 50 Fastest Growing Businesses in New York City, and named a Best Place to Work by multiple publications, including Vault’s Top 25 Best Accounting Firms to Work For, where it achieved the #1 ranking for Client Interaction.

A former Chair of Moore North America, Lou is a nationally recognized expert frequently called upon as a lecturer and advisor for companies and trade organizations. A frequent speaker and writer, he has authored numerous articles, served as a contributing editor to the Corporate Controller’s Manual, and taught graduate-level finance and accounting as an adjunct professor at Columbia University.

Lou has served as an executive board officer for the New York State Society of Certified Public Accountants (NYSSCPA) and is a member of the American Institute of Certified Public Accountants (AICPA). He is actively involved in community, civic and philanthropic organizations, including Futures in Education and St. Jude Children’s Research Hospital, and serves on the advisory board of the Northwell Cancer Institute. Lou also serves on the Boards of Flushing Financial Corp, a $6 billion U.S. bank, and BRT Realty, a publicly traded REIT.

A graduate of Queens College, Lou holds a degree in Business Administration in Accounting. He has completed postgraduate courses in taxation and earned the Certified Fraud Examiner (CFE) designation from the National Association of Certified Fraud Examiners.