About us


Our goal is to support efficiency and sustainability in the business operation of our clients and to solve the critical problems our clients may face based upon a trustworthy and sound business relationship.

The world has been rapidly transforming with the exponential development of the emerging technology, digitalization, and digital economy. The international regulations and systems have been complexly changing along with the digital technology transformation. In this rapidly and complexly changing international environment, our role is to help get our clients to understand the complex international regulations and systems, to rapidly adapt to the crucial changes, and to run their business more efficiently and sustainably.

Thank you.


Don J. Oh, CPA, CAA, MBA, MSc


• Certified Public Accountant (U.S.) (U.S. License# 36492)

• Foreign Certified Public Accountant (Korea) (Korea License# F00022)

• IRS Registered Tax Return Preparer (RPO)

• IRS ITIN & EIN Certifying Acceptance Agent (CAA)

• IRS EFTPS Batch Provider (TaxPro)

• FinCEN FBAR & BSA E-Filer (BSA)

• U.S. International Tax Consultant

• Tech Business Consultant

• QuickBooks Online Advanced Advisor

• University of Illinois at Urbana-Champaign, Master's Degree in Technology Management, Accountancy, and Corporate Governance and International Business 

• Sogang University, Master's Degree in Finance



• Current) KORUS Tax Accounting / Business Consulting - korusta.com

• Prior) Accounting firm in Korea (International team) 

• Prior) Accounting firm in the U.S.A

• Prior) Foreign-Invested Company (Tech business)

Professional area 


• U.S. Tax / International Tax

• U.S Company Accounting / Foreign-Invested Company Accounting

• Technology Advisory

Professional Networks  

Provide various customized services through Accounting/Tax, Laws/Visa, and Tech Business professional networks.

• Accounting/Tax

• Laws/Visa

• Tech Business


• KORUS Tax Accounting / Business Consulting

• e-Mail: cpa@korusta.com 

• Skype ID: live:cloudofficekorusta

• Tel. (KOR) +82-70-8680-9525

• Text (KOR) +82-70-8680-9525

• Fax (KOR) +82-507-0333-9565