Jack Sierk, CPA

Jack Sierk

Jack Sierk is a Certified Public Accountant and experienced tax professional specializing in R&D tax credits and Section 174 expense studies. As Tax Credit Senior Manager at Specialty Tax Group, Jack leads client engagements across diverse industries, helping businesses maximize their tax savings while ensuring compliance with evolving IRS regulations.

 

Before joining Specialty Tax Group, Jack spent several years at PwC, where he led a team of over 10 professionals delivering R&D tax credit and Section 174 capitalization studies. His leadership played a key role in expanding PwC’s international team and streamlining global operations to improve efficiency and quality. Jack began his career in public accounting with Aprio, preparing tax returns for individuals, partnerships, and corporations.

Jack holds a B.S. in Management and Accounting from The University of Alabama, where he graduated with honors from the Honors College and earned recognition on both the Dean’s and President’s Lists. He is a licensed Certified Public Accountant (CPA) and an active peer mentor with Best Buddies International, supporting individuals with intellectual and developmental disabilities.

 

Get To Know Jack Sierk

Why did you choose to work at STG?

I was drawn to STG’s collaborative culture and its focus on delivering real value to clients. The firm’s growth trajectory and commitment to excellence made it an exciting opportunity to contribute and make an impact.

 

What is your favorite aspect of your job?

I enjoy problem-solving — digging into the technical details of R&D studies, understanding how our clients innovate, and translating that into meaningful tax savings. Every project teaches me something new.

 

What’s your work style?

I believe in leading by example, staying organized, and empowering my team to succeed. Clear communication and attention to detail are key in our line of work.

 

What “bright idea” do you find yourself sharing over and over again?

Efficiency doesn’t mean cutting corners — it means refining processes so every step adds value.

 

What do you consider to be your best quality?

I’m process-oriented but people-first. Whether I’m mentoring a new team member or helping a client navigate complex tax rules, I focus on building trust and delivering results.

What did 10-year-old you want to be when you grew up?

An engineer or designer — I’ve always been fascinated by how things work and how to make them better.

What profession would you choose if you didn’t go into accounting?

Probably something in operations or management consulting — I love finding ways to improve systems and help teams perform at their best.