UK Startup to International Expansion: Adding US, AU, FR Subsidiaries

Last verified: 2026-05-02

A UK Ltd that signed its first $50k US contract often follows the same pattern: first a US enterprise customer asks for a Delaware Inc., then an Australian customer wants a local invoicing entity, then a French employee needs a CDI. This guide walks the lifecycle of a UK Ltd adding subsidiaries in the US, Australia, and France — with the corporate paperwork, the bank accounts, the employer-registration steps, and the most common errors.

Quick Answer (TL;DR)

• Use a UK Ltd as parent and incorporate wholly-owned subsidiaries in each new market — cleanest separation of liability, tax, and employer obligations.
• US first move: Delaware C-Corp subsidiary, EIN, payroll registration, state nexus by sales activity.
• AU first move: Pty Ltd subsidiary, ABN/TFN, PAYG withholding, single-touch payroll, AU-resident director under s.201A.
• FR first move: SAS or succursale (branch) — SAS for permanent presence with French employees; succursale for limited representation.
• Watch transfer pricing (UK Finance Act 1998 Schedule 18, OECD TPG 2022) on every intercompany invoice from day one.

Comparison Table at a Glance

The 6-Stage Lifecycle

Stage 1 — Confirm UK Ltd Parent Structure

Before adding any subsidiary, confirm the UK parent is in order:

• Companies Act 2006 s.853A confirmation statement filed up to date.
• PSC register under CA 2006 Part 21A complete.
• ECCTA 2023 identity verification for all directors and PSCs (rolling out 2026).
• Articles of association allow share issuance by board resolution (Model Articles default works).
• Group structure decision: flat parent → subsidiaries, OR holdco + UK trading sub + foreign subs (better for Series A flip).

Tax flag: A UK parent with foreign subsidiaries must file Country-by-Country Reports if group revenue ≥ €750m, transfer pricing documentation under FA 1998 Sch 18 even at startup scale, and CFC (Controlled Foreign Companies) rules under TIOPA 2010 Part 9A.

Stage 2 — Adding a US Delaware C-Corp Subsidiary

Statute: DGCL §101 (incorporation), §141 (board), §151 (stock).

Step-by-step:

1. File Certificate of Incorporation with Delaware Division of Corporations. Use 10,000,000 authorised shares at $0.0001 par value.
2. Appoint Delaware registered agent (mandatory under DGCL §132) — Harvard Business Services or similar, ~$50/year.
3. Pass first board resolutions: appoint officers, adopt bylaws, authorise share issuance to UK Ltd parent (e.g., 8,000,000 common shares for $800).
4. Apply for EIN via Form SS-4 by mail or fax (foreign-officer route). 4–6 weeks.
5. Open bank account at Mercury or Brex (foreign-owned subsidiary). Personal visit not required.
6. State qualifications. If you have employees or office in California, qualify as a foreign corporation under California Corp Code §2105. Same for New York (BCL §1304), Texas, etc.
7. State payroll registration in every state with employees: state unemployment ID + state withholding ID.
8. Federal payroll: Form 941 quarterly + Form 940 annual.

Common error. Founders forget that physical presence + employees in California = California franchise tax + corporate income tax + LLC/Corp registration even though incorporated in Delaware. State nexus follows the people, not the certificate.

Source: https://corp.delaware.gov/

Stage 3 — Adding an Australian Pty Ltd Subsidiary

Statute: Corporations Act 2001 (Cth) s.117 (registration), s.201A (director residency), s.201B (DIN).

Step-by-step:

1. Find an Australian-resident director — co-founder, trusted employee, or nominee director service. The s.201A requirement is the largest blocker for foreign expansion.
2. Obtain Director Identification Numbers for all directors (Australian and foreign). Foreign directors apply by paper to ABRS (28 days).
3. Reserve company name at ASIC Connect (optional but recommended).
4. Register company via Form 201, fee A$597. Issue 1 ordinary share to UK Ltd parent.
5. Apply for TFN and ABN at Australian Business Register; allow 28 days.
6. Register for GST if turnover will exceed A$75,000.
7. Register as employer: PAYG withholding + Single Touch Payroll (STP) via accounting software (Xero, MYOB).
8. Pay superannuation at 11.5% (FY 2025–26) of Ordinary Time Earnings to each employee’s nominated super fund within 28 days of quarter-end.

Common error. Many founders rely on UK Ltd seconding an employee to Australia and treating them as a UK contractor. ATO will deem this a permanent establishment (Income Tax Assessment Act 1936 s.6(1)) after 6 months — triggering full Australian corporate tax retroactively.

Source: https://asic.gov.au/

Stage 4 — Adding a French SAS Subsidiary

Statute: Code de commerce L.227-1 (SAS); Code du travail (employment).

Step-by-step:

1. Decide SAS vs branch. A succursale (branch) is faster but creates direct liability for UK parent and triggers French corporate tax on local profits anyway. A SAS is the cleaner choice for any operation with French employees.
2. Draft statuts in French. Minimum capital €1 (50% paid in at incorporation).
3. Open compte de capital at a French bank or Qonto/Shine. Deposit at least 50% of subscribed capital.
4. Publish a legal announcement in a journal d’annonces légales (JAL). Cost €150–€220.
5. File via Guichet Unique INPI: statuts, declaration of beneficial owner (RBE), JAL receipt, justificatif de domicile of registered office, declaration of non-condamnation of Président. Fee €37.45.
6. Receive K-bis (extract from RCS) — typically 7–14 days.
7. Register for SIREN/SIRET, VAT (TVA intracommunautaire) automatically through Guichet Unique.
8. Register with URSSAF as employer before first hire. Obtain numéro employeur.
9. Pay social contributions (~42% on top of gross salary employer-side, ~22% employee-side).
10. Issue bulletin de paie monthly and submit DSN (déclaration sociale nominative) — automatic via payroll software.

Common error. UK founders treat the French SAS like a UK Ltd and try to operate without a French expert-comptable. French liasse fiscale, DSN, CVAE, and CFE filings are non-trivial. Budget €3,000–€7,000/year for an expert-comptable.

Source: https://www.guichet-unique.inpi.fr/

Stage 5 — Intercompany Agreements (Day One)

For each new subsidiary you must put intercompany contracts in writing before the first invoice flows:

The arms-length principle applies to every intercompany transaction. Document the methodology in a transfer pricing study and review annually.

Source: OECD Transfer Pricing Guidelines 2022 — https://www.oecd.org/tax/transfer-pricing/

Stage 6 — Ongoing Group Compliance Calendar

Common Pitfalls (Gyoseishoshi View)

1. Treating UK Ltd seconded employees as not creating PE in AU/FR. They almost always do.
2. Sending a wire from UK Ltd to “open” the US sub bank account without an intercompany loan agreement — the IRS will recharacterise as capital, with tax consequences.
3. Forgetting France URSSAF registration before first hire — fines can reach €5,000+ plus retroactive contributions.
4. Missing Delaware annual report by 1 March — corporation enters bad standing, cannot file for state qualifications elsewhere.
5. Not appointing an Australian-resident director until after first contract — Pty Ltd is technically defective and ASIC may cancel.
6. Failing to do transfer pricing documentation at startup scale because “we are too small” — HMRC and ATO routinely audit small groups.

Conclusion

A UK Ltd parent + US Delaware Inc. + Australian Pty Ltd + French SAS is a typical first-year group structure for a UK SaaS that signs an early US enterprise customer. Each subsidiary takes 6–12 weeks of preparation: identity work, registered agents, employer registration. Plan in parallel — the order is usually US first (because customers ask for it), then AU when the first AU sales-rep hire is imminent, then France when the first French employee signs a CDI.

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Disclaimer

Legal information, not legal advice. MmowW Scrib🐮 is operated by a licensed Gyoseishoshi (行政書士) office in Japan. We are not solicitors, barristers, attorneys, avocats, or licensed legal practitioners in any jurisdiction.

Sources

• UK Companies Act 2006: https://www.legislation.gov.uk/ukpga/2006/46/contents
• UK ECCTA 2023: https://www.legislation.gov.uk/ukpga/2023/56
• UK TIOPA 2010 (CFC rules): https://www.legislation.gov.uk/ukpga/2010/8
• US Delaware DGCL: https://delcode.delaware.gov/title8/c001/
• US IRS Form SS-4: https://www.irs.gov/forms-pubs/about-form-ss-4
• US FinCEN BOI: https://www.fincen.gov/boi
• Australia Corporations Act 2001: https://www.legislation.gov.au/Details/C2024C00010
• Australia ABRS DIN: https://www.abrs.gov.au/director-identification-number
• Australia ATO PAYG: https://www.ato.gov.au/business/payg-withholding/
• France INPI Guichet Unique: https://www.guichet-unique.inpi.fr/
• France URSSAF employer: https://www.urssaf.fr/portail/home/utile-et-pratique/embaucher-un-salarie.html
• OECD Transfer Pricing Guidelines 2022: https://www.oecd.org/tax/transfer-pricing/