About Us
Built for businesses that need clarity, confidence, and execution.
JCK Yoonsung LLP is a U.S.-based CPA and advisory firm serving domestic and multinational organizations.
Our firm
We provide audit, tax, accounting advisory, transaction advisory, and financial advisory services to businesses across the United States and global markets.
Our partners bring extensive Big Four and industry experience, enabling us to combine technical quality with a responsive, hands-on service model.
We are particularly well known for Korea–U.S. cross-border matters, but our platform is designed for a broader client base: U.S. businesses, global groups, private companies, investors, and organizations seeking practical financial guidance.
Our Difference
What clients can expect.
Technical excellence
Strong experience in U.S. GAAP, IFRS, K-IFRS, group reporting, internal controls, and complex financial reporting matters.
Responsive service
Direct access to experienced professionals who understand timing, communication, and execution.
Business perspective
Advice that considers both technical accounting requirements and the operational realities of management teams.
Global mindset
Experience coordinating with headquarters, local teams, investors, advisors, and group auditors across jurisdictions.