January 30, 2026 – CohnReznick, a leading professional services firm, announced today that Marco Sideri has joined the firm as a Financial Sponsors Tax Partner in its Boston office. Sideri brings extensive experience advising top-tier private equity firms, venture funds, hedge funds, and other alternative asset managers on complex tax matters and delivering tax co-sourcing and outsourcing solutions for asset and wealth managers.

Sideri’s expertise comprises tax compliance, complex transaction work, preparing and reviewing complex book-to-tax calculations, portfolio company transaction analyses, quarterly fund estimates, FDAP and ECI withholding calculations, and partnership and corporate tax forms. Additional experience includes establishing and advancing tax technology and transformation initiatives, leveraging tools such as Alteryx, Python, and generative AI (LLMs) to enhance automation, accuracy, and scalability of tax processes.

“Marco has adeptly guided clients through intricate tax challenges, from structuring and transaction planning to operational compliance, and has championed the use of technology to improve accuracy and scalability,” said Jeremy Swan, Managing Partner –  Financial Sponsors & Financial Services. “His ability to combine deep technical knowledge with a client-first approach will help our clients manage complexity with confidence and enhance the value we provide. Additionally, Marco’s extensive financial sponsors and tax expertise will be integral to the continued expansion of our practice.” 

Sideri joins CohnReznick from a top 10 accounting firm, where he served as Managing Director and Co-Leader of the Private Equity Tax Co-Sourcing Practice. Prior to that, he spent more than 15 years at a Big Four firm in its Financial Services practice. He holds a Master of Science in Accounting and a Bachelor of Science in Accounting & Economics from Boston College and is a Certified Public Accountant in Massachusetts.