Katie Castelli

Years Experience

10 years


Bryant University
M.S. in Accountancy
B.S. in Business Administration

Industry Expertise

Biotechnology, Life Sciences, Medical Devices

Big Four Alma Mater


Katie Castelli

Manager – Tax

Katie brings corporate income tax compliance and reporting experience to WilliamsMarston. Since joining WilliamsMarston, Katie has advised clients in the software, biotechnology, life sciences, and manufacturing industries on a variety of income tax matters, including annual and interim income tax provision preparation and the related financial statement disclosures, as well as other corporate tax matters.

Prior to joining WilliamsMarston, Katie worked in EY LLP’s Global Compliance & Reporting practice in Boston. While at EY, Katie prepared US federal, state and foreign income tax returns, prepared and audited the tax provisions for domestic and multinational entities, and performed a wide variety of tax advisory services. Katie’s industry experience includes biotechnology, medical devices, and life sciences, amongst others.

Katie holds a Master of Professional Accountancy degree and a Bachelor of Science degree in Business Administration with a concentration in Accounting from Bryant University.