(914) 798-9990

Our People

Our people make the difference. GMG CERTifyTax’s team includes experienced state and local tax experts who can provide meaningful insight into your liability, mitigate the exposure, and prevent the exposure from recurring. We offer actionable, personalized information about your risk.

Tom McCarthy

Partner, New York
Fordham University, B.A., J.D.

Email: tmccarthy@gmgconsulting.com
Phone: (914) 798-9902

Tom has an extensive tax and legal background, and has practiced federal and state and local tax for more than 20 years. He provides general tax consulting to a variety of large corporations, and works closely with his clients to address their tax needs.

Tom’s extensive legal, federal tax and financial accounting expertise sets him apart from other state tax specialists. Tom also has considerable experience in managing restructuring projects for large, multinational corporations, and is adept at identifying and resolving the business/operational issues associated with the restructurings.

Before founding GMG, Tom was a partner at PricewaterhouseCoopers LLP in charge of the State and Local Tax optimization group. Tom also worked at a law firm for several years specializing in corporate and tax law. Tom has a B.A. and J.D. from Fordham University, and was a recipient of the Cornelius Ahern Scholarship, a three-year law scholarship awarded to one student annually based on academic achievement.

Zach Grant

Partner, New York
City University of New York, Queens, B.A.
Benjamin N. Cardozo School of Law, J.D.

Email: zgrant@gmgconsulting.com
Phone: (914) 798-9901

Zach has a broad background in federal income tax and over 30 years of experience specializing in state and local income taxes, sales and use taxes, credits and incentives and miscellaneous transactional tax issues. Zach has considerable expertise in the state and local income tax implications of mergers and acquisitions, managing and settling controversies and income /franchise tax planning. His clients include several Fortune 500 companies engaged in the retail, technology, utility and financial services sectors.

Zach has worked extensively with audit teams, supervisors and managers in state revenue departments across the United States. He has represented taxpayers and negotiated settlements in hundreds of controversies involving income. sales and use, property. commercial rent, gross receipts and real property transfer taxes.

Prior to founding GMG in 2001, Zach was a partner in the State and Local Tax practice at PricewaterhouseCoopers LLP. He is a member of the New York State Bar and American Bar Association.

Joe Haller

Partner, San Francisco
Stanford University, A.B.
Columbia University, J.D., M.B.A.
NYU School of Law, LL.M.

Email: jhaller@gmgconsulting.com
Phone: (415) 227-2401

A partner in Grant McCarthy Group’s San Francisco office, Joe has over twenty years experience dealing with federal and state corporate tax issues. His practice includes federal and state taxation, with a focus on the high tech and utility industries. Joe has significant experience leading large-scale tax research and restructuring projects. He has also worked extensively with corporate clients in resolving federal and state tax audits. Joe’s legal and business education, along with his professional experience, allow him to work with clients to understand the full financial impact of tax planning, audits, and restructurings.

Prior to joining GMG, Joe was a manager in the Tax and Legal Services practice in PricewaterhouseCoopers LLP’s New York office. Joe is a regular speaker at regional and national tax seminars. His recent presentations have generally involved California and federal tax matters, and have included tax and accounting issues affecting utilities.

Joe received an A.B. from Stanford University, a J.D. from Columbia University and an LL.M. in Taxation from New York University School of Law. Joe also received an M.B.A. from Columbia University. He is admitted to practice law in California and in New York State.

Ray Diaz

Director Of Operations, Connecticut
Siena College, B.A.
Albany Law School of Union University, J.D.

Email: rdiaz@gmgconsulting.com
Phone: (914) 798-9925

Ray has a broad-based tax background and has specialized in state and local tax for more than 12 years. His practice is concentrated in sales and use tax audit defense and the reduction of liabilities related to exempt sales. He also provides sales and use tax consulting to a variety of large corporations, and works closely with his clients to address their tax needs.

Ray has considerable experience with tax technology and has performed exemption certificate management projects for a variety of large, multinational corporations. He is adept at identifying, managing and resolving the tax and compliance issues related to exempt sales, as well as identifying and resolving the business/operational issues associated with monitoring and managing his clients’ exempt sales.

Ben Isbell

Sales, Alabama
Montana State University, B.S.

Email: bisbell@certifytax.com
Phone: (205) 470-1587 

Ben has 15 plus years of experience specializing in tax automation and directing sales efforts. Ben leads GMG CERTifyTax business development efforts providing a multitude of services to GMG CERTifyTax clients in various industries, including telecommunications, energy and retail verticals. His experience includes: working with Fortune 500 companies on complex tax automation projects, developing and maintaining alliance relationships, and ERP specific tax automation integrations. Prior to joining GMG CERTifyTax, Ben spent 14 years with Wolters Kluwer managing the Telecommunications and Energy sales portfolios in the WK Atlanta office. Since joining GMG CERTifyTax in 2019, Ben has provided leadership in the firms go-to-market strategy for GMG CERTifyTax. He has also been instrumental in understanding client requirements and developing sales methodologies to drive positive customer engagements. His experience includes: designing and implementing channel specific partner programs, collaborating across all levels of an organization, and maintaining a client-first agenda.

Call (914) 798-9990 to speak with our experts or request information from our sales team by clicking here to help provide a solution to your business needs.