Education
Texas A&M University
M.S. in Finance
B.B.A. in Accounting
Ryan Diehl
Partner – OneStream Practice Leader
Ryan brings more than 17 years of experience to WilliamsMarston. As OneStream Practice Leader, he leads teams in delivering high‑impact OneStream implementations for enterprise and private equity-backed clients. With deep expertise in corporate performance management and financial systems design, he partners closely with CFOs, controllers, and their finance organizations to build scalable, efficient, and future‑ready consolidation, planning and reporting environments.
Before joining WilliamsMarston, Ryan was with AIT Consulting, acquired by WilliamsMarston in 2025. Prior to AIT, Ryan was a Senior Director at Alvarez & Marsal where he advised clients in the Energy and Distribution industries on financial close consolidations, budgeting and forecasting transformations, long‑term strategic financial modeling, and improved end‑of‑period and SEC reporting processes. He has deep experience managing enterprise financial software implementations, including OneStream XF, SAP BPC, and Hyperion Planning, Essbase, and Hyperion Financial Management.
Ryan is a Certified Public Accountant in the State of Texas and is a OneStream Certified Professional (OCP) – Lead Architect R1.
Ryan holds a Master of Science in Finance from Texas A&M University and a Bachelor of Business Administration degree in Accounting from Texas A&M University.