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U.S. Business Formation Education — Advanced

Professional guide for tax, compliance, and long-term operations

Section 01

Mastering Form 5472

Form 5472 is used to report transactions between a foreign-owned U.S. corporation and its related parties to the IRS. If you are a Korean founder with a U.S. entity, you almost certainly have a filing obligation.

Non-filing penalty: $25,000 / form / year

Failure to file or filing an incomplete Form 5472 results in a $25,000 penalty per form per year. Additional $25,000 penalties accrue every 90 days after IRS notice if not corrected.

Form 5472 Filing Decision Flowchart

Do you own a U.S. entity (LLC or Corp)?
YES
Is 25%+ owned by a foreign person (non-resident)?
YES
Are there Reportable Transactions?
YES
Must file Form 5472
NO
Verify even without transactions
NO
Not applicable
NO
Not applicable

Single-Member LLC Special Note

Since 2017, foreign-owned disregarded entities (Single-Member LLCs) are also required to file Form 5472, along with a pro-forma Form 1120.

Reportable Transaction Types

Transaction TypeExamples
Loans (lending/borrowing)Owner funds the entity, entity lends to owner
Services provided/receivedIncludes unpaid services by owner for the entity
Capital contributionsInitial or additional capital injections
DistributionsProfit distributions from entity to owner
Sale of tangible/intangible assetsIP transfers, equipment sales

Penalty Scale Comparison

Form 5472 non-filing$25,000/yr
Record-keeping violation$10,000
BOI non-reporting$591/day
FBAR non-filing (non-willful)$10,000/acct/yr
FBAR non-filing (willful)$100,000+
Section 02

Tax Calendar (Advanced)

Key filing and payment deadlines organized by month for U.S. business operations. Missing deadlines triggers penalties and interest, so calendar management is essential.

JAN
  • Q4 estimated tax (1/15)
  • W-2 / 1099-NEC issuance (1/31)
MAR
  • Form 1065 (Partnership) (3/15)
  • Form 1120-S (S-Corp) (3/15)
  • K-1 issuance deadline
  • DE Corp Annual Report (3/1)
APRCRITICAL!
  • Form 1120 (C-Corp) (4/15)
  • Form 5472 filing (4/15)
  • 1040-NR (4/15)
  • Q1 estimated tax (4/15)
  • FBAR filing (4/15)
  • CA $800 minimum tax
MAY
  • FL Annual Report (5/1)
  • TX Franchise Tax (5/15)
JUN
  • Q2 estimated tax (6/15)
  • Overseas US person extension (6/15)
  • DE LLC Annual Tax (6/1)
SEP
  • Q3 estimated tax (9/15)
  • 1065 / 1120-S extension deadline (9/15)
OCT
  • 1120 extension deadline (10/15)
  • 1040-NR extension (10/15)
  • FBAR extension deadline (10/15)

Legend

Federal
State
Critical

Form 7004 extension = filing deadline extension, NOT payment deadline extension!

Even with an extension, estimated taxes must be paid by the original deadline. Underpayment triggers interest and penalties.

Section 03

Korea-U.S. Tax Treaty

South Korea and the U.S. have a tax treaty to prevent double taxation. The treaty reduces or eliminates withholding rates depending on income type.

Income TypeWithout TreatyWith TreatyArticle
Business Income-Not taxed without PEArt. 7
Dividends30%15% / 10%(general 15%, 10%+ ownership 10%)Art. 12
Interest30%12%Art. 13
Royalties30%15% / 10%(general 15%, industrial/scientific 10%)Art. 14
Independent Personal Services-Not taxed without fixed baseArt. 15

To claim treaty benefits, you must submit W-8BEN-E (entity) or W-8BEN (individual) to the income payer.

Without the form, the default 30% withholding applies. W-8BEN-E must be renewed every 3 years.

Permanent Establishment (PE)

Recognized as PE

  • Branch, office, factory, workshop
  • Construction/installation site exceeding 6 months
  • Dependent agent with authority to conclude contracts
  • Server/fixed equipment (debatable)

NOT Recognized as PE

  • Facility solely for storage/display
  • Facility solely for purchasing or collecting info
  • Activities through an independent agent
  • Auxiliary or preparatory activities
Section 04

Corporate Transparency Act & BOI Reporting

The Corporate Transparency Act (CTA) requires businesses to report Beneficial Ownership Information (BOI) to FinCEN. Its purpose is to prevent money laundering, terrorist financing, and tax evasion.

BOI Reporting Deadlines

Formation DateFiling Deadline
Formed before Jan 1, 2024By January 1, 2025
Formed Jan 1 - Dec 31, 2024Within 90 days of formation
Formed after Jan 1, 2025Within 30 days of formation
When information changesWithin 30 days of change

BOI Reporting Legal Uncertainty

Multiple court rulings in 2024-2025 have resulted in temporary stays on CTA enforcement. Despite legal uncertainty, it is safest to prepare and file BOI reports when possible, as retroactive enforcement remains possible once the law is finalized. Check the FinCEN website (fincen.gov/boi) for the latest updates.

Section 05

Key Forms Reference

Key IRS and FinCEN forms required for U.S. business operations.

FormPurposeDue DateNotes
Form SS-4EIN applicationImmediately after formationOnline/fax/mail available
Form 5472RequiredForeign-owned entity transaction report4/15 (C-Corp), 3/15 (LLC)$25,000 penalty if not filed
Form 1065Partnership information returnMarch 15K-1 must also be issued
Form 1120C-Corp income tax returnApril 15Flat 21% tax rate
Form 7004Automatic 6-month extensionBefore original due datePayment deadline NOT extended!
FBAR (FinCEN 114)Foreign financial account report4/15 (auto-extended 10/15)Required if balance exceeds $10,000
W-8BEN-EForeign entity treaty benefit claimBefore income is paidMust renew every 3 years
Section 06

Checklists

Essential tasks after formation and annual compliance items organized for easy tracking.

Post-Formation 30-Day Checklist

  • checkboxObtain EIN (Form SS-4)Immediately
  • checkboxOpen bank account1-2 weeks
  • checkboxDraft Operating AgreementAt formation
  • checkboxDeposit initial capitalAfter account opening
  • checkboxBOI reportWithin 30 days
  • checkboxSet up accounting system1 month
  • checkboxConnect payment processorAs needed

Annual Compliance Checklist

  • checkboxAnnual ReportVaries by state
  • checkboxFranchise tax paymentVaries by state
  • checkboxBusiness tax return (1120/1065)3/15 or 4/15
  • checkboxFile Form 5472With tax return
  • checkboxQuarterly estimated taxQ1-Q4
  • checkboxFile FBAR4/15 (ext. 10/15)
  • checkboxRenew Registered AgentAnnually
  • checkboxUpdate BOI (if changed)30 days after change
Section 07

Professional Guidance

Complex tax and compliance matters require professional help. Choose the right professional based on your situation.

SituationRecommended ProfessionalEstimated Cost
Annual tax filing (LLC)CPA / EA$500 ~ $2,000
Form 5472 + Pro-forma 1120CPA (international tax exp.)$500 ~ $1,500
Cross-border US-Korea filingUS-Korea cross-border CPA$1,500 ~ $5,000+
Entity formation/structuringBusiness Attorney$1,000 ~ $5,000
BOI report filingAttorney / CPA$200 ~ $500
IRS audit representationCPA / Tax Attorney$3,000 ~ $10,000+

Key Points When Choosing a Professional

  • - Verify experience with US-Korea cross-border tax.
  • - Ask about their experience filing Form 5472.
  • - Clarify the fee structure (hourly vs. flat) upfront.
  • - Confirm they hold CPA or EA credentials.
  • - Check if they communicate in your preferred language.

This document is for general educational purposes only and does not replace legal, tax, or accounting advice. Application varies by individual circumstances, so always consult a qualified professional (CPA, EA, or attorney).

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