Once you set up a US company, annual tax filing obligations come with it. There are a few items that are especially easy to miss when a Korean company owns a US entity — here's a basic checklist to keep in mind.
Start With: Both Federal and State Taxes
The US requires filing with both the federal government and state governments. You may have filing/payment obligations not just in the state where you actually operate, but also in the state where you incorporated (e.g., Delaware) — so both need to be tracked.
Filing Forms Differ by Entity Type
Whether you set up an LLC or a C-Corp/S-Corp determines which federal tax form applies (e.g., an LLC taxed as a partnership files Form 1065, while a C-Corp files Form 1120). The tax election you made at formation continues to shape how you file every year, so that early decision matters long-term.
What Korean Owners of US Entities Often Miss: Form 5472
A US company that is 25%+ owned by a foreign person or foreign entity must separately file Form 5472, reporting related-party transactions. Missing this filing can trigger significant penalties — so if your structure involves funds or transactions flowing between your Korean parent company and the US entity, this deserves extra attention.
EIN, Registered Agent, and Annual Reports
Beyond getting an EIN (federal tax ID) after formation, you also need to maintain a Registered Agent every year and file a state Annual Report with the associated fee — missing these can result in your entity being administratively dissolved.
Sales Tax Is a Separate Issue
Apart from corporate income tax, once sales in a given state cross a certain threshold, you may trigger Sales Tax collection/filing obligations (Nexus). This is especially relevant if you sell across multiple states through online channels like Amazon — understanding where you've triggered Nexus matters.
Keep Books Monthly, Not All at Once at Filing Time
Trying to organize a full year of books right before the filing deadline makes it easy to miss items. Keeping monthly records of income and expenses significantly reduces the burden when tax season arrives.
Key Takeaways
Track both federal and state taxes, confirm the right form for your entity type, don't forget Form 5472 if you're a foreign-owned entity, and check Sales Tax Nexus separately. Keeping your books current throughout the year is the most reliable way to make tax season manageable.