Business structure is one of those decisions that most consultants delay, get wrong by default, and pay for in unnecessary taxes for years before fixing it.

The good news: the right structure is not complicated for most solo consultants and small agencies. The bad news: the default structure — sole proprietor or single-member LLC — is almost certainly not optimal once your income exceeds $50,000–$80,000/year.

This guide explains the practical legal and tax structure options for consultants in the USA, UK, and Australia, when each structure becomes beneficial, and how to set it up.

Disclaimer: This is educational information, not legal or tax advice. Consult a qualified accountant or attorney licensed in your jurisdiction before making structural decisions.

Table of Contents

USA: LLC vs S-Corp for Consultants

The Four Main US Business Structures

Structure Liability Protection Tax Treatment Best For
Sole Proprietorship None Self-employment tax on all net income Under $30K/year or just testing idea
Single-Member LLC Yes Same as sole prop by default Under $60K/year, simplicity priority
LLC taxed as S-Corp Yes Salary + distribution split Over $60K net income
C-Corporation Yes 21% flat corporate rate, double taxation VC-funded startups, equity plans

The Self-Employment Tax Problem

As a sole proprietor or single-member LLC, every dollar of net business income is subject to self-employment (SE) tax:

  • 15.3% on the first $160,200 of net income (2024)
  • 2.9% on income above $160,200 (no Social Security, only Medicare)

On $100,000 in net consulting income, SE tax is approximately $14,130 — on top of federal income tax.

The S-Corp Solution

An S-Corp election (filed on Form 2553) changes how your LLC income is taxed. Instead of all income being subject to SE tax, you split income into:

  1. Salary (W-2) — subject to payroll taxes (15.3% split between employer and employee)
  2. S-Corp distributions — NOT subject to SE tax

Example: $100,000 Net Income

  Sole Prop / Default LLC LLC with S-Corp Election
Total Net Income $100,000 $100,000
Reasonable Salary — $60,000
S-Corp Distribution — $40,000
SE Tax / Payroll Tax $14,130 $9,180 (on $60K salary only)
SE Tax Savings — $4,950/year
Additional accounting cost $0 ~$1,500/year
Net Annual Benefit — ~$3,450

At $150,000 in net income, the savings expand to $8,000–$10,000/year — well above the accounting overhead.

When to Elect S-Corp Status

The threshold: S-Corp election typically makes sense when net business income exceeds $60,000/year consistently.

Below $60,000/year: Additional accounting costs ($1,500–$2,500 for a CPA to handle S-Corp payroll and tax returns) may offset or exceed the tax savings.

The mechanics:

  1. Form an LLC in your state (or use an existing LLC)
  2. File Form 2553 with the IRS to elect S-Corp treatment
  3. Set up payroll for your owner-employee salary (Gusto, QuickBooks Payroll, or ADP)
  4. Pay yourself a regular salary via payroll
  5. Take additional profits as distributions (not subject to SE tax)
  6. File Form 1120-S annually (S-Corp tax return)

S-Corp pitfalls to avoid:

  • Setting salary unreasonably low — the IRS targets S-Corps where distributions heavily dwarf salary as evidence of under-classified compensation
  • Missing payroll deposit deadlines — payroll taxes must be deposited per a schedule based on payroll amount
  • Not accounting for state-specific S-Corp rules — some states do not recognize S-Corp status or charge additional fees

UK: Sole Trader vs Limited Company

UK Business Structure Options

Structure Setup Admin Burden Tax Treatment
Sole Trader Minimal (register with HMRC) Low Personal rates up to 45% + NI
Partnership Register with HMRC Moderate Same as sole trader per partner
Limited Company Companies House registration Higher 19–25% corporation tax

Sole Trader: Simple but Expensive at Scale

As a UK sole trader, all business profits are taxed as personal income:

  • Personal allowance: £12,570 tax-free (2024/25)
  • Basic rate: 20% on £12,571–£50,270
  • Higher rate: 40% on £50,271–£125,140
  • Additional rate: 45% above £125,140

Plus Class 4 National Insurance: 9% on profits £12,570–£50,270, 2% above.

On £80,000 profit as a sole trader, you pay approximately £28,000 in income tax + NI. Net take-home: ~£52,000.

Limited Company: Tax Efficient at Higher Income

Operating through a UK Limited Company:

  1. Company pays corporation tax on profits: 19% up to £50,000 profit; 25% above £250,000 (with small profits relief in between)
  2. Director pays themselves a salary just below NI thresholds (approximately £12,570/year)
  3. Remaining profit extracted as dividends taxed at:
    • Basic rate: 8.75%
    • Higher rate: 33.75%
    • Additional rate: 39.35%

Example: £80,000 Profit

  Sole Trader Limited Company
Business profit £80,000 £80,000
Salary (director) — £12,570
Corporation tax (19%) — (£12,863)
Post-tax company profit — £54,567
Dividend extraction — £54,567
Personal dividend tax (8.75% basic) — (£3,598)
Total tax paid ~£28,000 ~£16,461
Net take-home ~£52,000 ~£63,539

Annual tax saving: ~£11,500 — enough to justify the additional accounting costs of running a limited company.

When a UK Limited Company Makes Sense

Typically: when consistent profit exceeds £40,000–£50,000/year.

Below this threshold: professional accounting fees for a limited company (£1,000–£2,500/year) often consume much of the tax saving.

Additional benefits of UK Limited Company:

  • Limited liability protection (personal assets protected from business debts)
  • More credible for larger clients and government contracts (some require limited company status)
  • Ability to retain profits in the company and extract them in future lower-income years
  • Simpler to bring in business partners or investors

Setup process:

  1. Register with Companies House (online, ~£12, completed in 24 hours)
  2. Set up a business bank account
  3. Register for corporation tax with HMRC
  4. Register for VAT if turnover will exceed £90,000/year (2024 threshold)
  5. Hire a UK accountant — essential for compliant director payroll and annual accounts

Australia: Sole Trader vs Pty Ltd vs Trust

Australian Business Structure Options

Structure Tax Rate Complexity When to Use
Sole Trader Personal marginal (up to 47%) Low Under $80K net profit
Pty Ltd Company 25% (base rate) or 30% Moderate-High Over $80–100K net profit
Discretionary Trust Distributed to beneficiaries High Multiple family members, significant assets
Unit Trust Distributed proportionally High Multiple investors, property

Sole Trader in Australia

Simple structure: register your ABN, file an individual tax return including business income on your Schedule.

Tax burden (2024/25, Australian residents):

Income Band Tax Rate
$0–$18,200 0% (tax-free threshold)
$18,201–$45,000 19%
$45,001–$120,000 32.5%
$120,001–$180,000 37%
$180,001+ 45%

Plus 2% Medicare levy on most income.

At $120,000 net profit: ~$34,297 in income tax + $2,400 Medicare = ~$36,697 total. Net take-home: ~$83,303.

Pty Ltd Company in Australia

Australian companies with less than $50 million annual turnover and at least 80% of income from business activities pay the base rate entity tax rate of 25% (down from 30%).

Owner extraction strategy:

  • Pay yourself a salary (deductible to the company)
  • Leave remaining profits in the company at 25% tax
  • Extract further as fully franked dividends when needed (with franking credits offsetting personal tax)

Example: $120,000 Net Profit

  Sole Trader Pty Ltd
Business profit $120,000 $120,000
Salary to owner — $80,000
Company profit — $40,000
Company tax (25%) — ($10,000)
Remaining in company — $30,000
Personal tax on $80K salary — ~$18,097
Total tax extracted year 1 ~$36,697 ~$28,097
Net take-home (extracted) ~$83,303 ~$91,903

Annual saving at $120,000 profit: ~$8,600.

Trust Structures (Advanced)

A discretionary (family) trust allows the trustee to distribute income among beneficiaries each year — typically the owner and family members in lower tax brackets. This can be highly tax-efficient for high-income consultants with a partner or children who have lower personal income.

Trusts are more complex and expensive to administer. Setup costs $1,500–$3,000; annual accounting costs $2,000–$5,000+. Appropriate for consultants earning $200,000+ net profit consistently.

Important: Trust structures require advice from an Australian registered tax agent or accountant. Rules around trust distributions have tightened significantly in recent years.

Comparing Structures by Income Level

USA Consultants

Annual Net Profit Recommended Structure Reason
Under $30,000 Sole Prop or LLC Simplicity; low tax savings from S-Corp
$30,000–$60,000 Single-Member LLC Liability protection without S-Corp complexity
$60,000–$500,000 LLC taxed as S-Corp Meaningful SE tax savings
$500,000+ S-Corp or C-Corp Depends on equity plans and investor structure

UK Consultants

Annual Net Profit Recommended Structure
Under £30,000 Sole Trader
£30,000–£50,000 Evaluate (borderline for Ltd)
£50,000+ Limited Company

Australian Consultants

Annual Net Profit Recommended Structure
Under $80,000 Sole Trader
$80,000–$200,000 Pty Ltd
$200,000+ Pty Ltd + Trust (with accountant advice)

The Corporate Veil: Why Structure Protects You

The liability protection from an LLC, limited company, or Pty Ltd is not automatic — it requires maintaining the separation between personal and business affairs.

Actions that pierce the corporate veil (and eliminate protection):

  • Using business accounts for personal expenses (co-mingling)
  • Failing to keep proper financial records
  • Under-capitalizing the company (running it without sufficient funds to meet obligations)
  • Personally guaranteeing business debts without understanding the implications
  • Operating a shell company without real business activity

Actions that preserve protection:

  • Maintaining a separate business bank account
  • Always invoicing through the business entity
  • Keeping personal and business expenses completely separate
  • Filing required annual reports and compliance documents on time
  • Keeping meeting minutes (for corporations) or operating agreement (for LLCs) current

Steps to Set Up Your Business Structure

USA: Forming an LLC with S-Corp Election

  1. Choose your state of formation. Most consultants form in their home state. Delaware and Wyoming are popular for specific legal benefits, but add complexity. For a simple consulting LLC, home state formation is usually optimal.
  2. File Articles of Organization with your state. Online through your state’s Secretary of State website. Most states complete this in 1–5 business days (California may take 15+ days). Fee: $50–$500 depending on state.
  3. Get an EIN (Employer Identification Number). Free, instant, at IRS.gov. Required for banking, payroll, and tax filing.
  4. Draft an Operating Agreement. Even for a single-member LLC, this documents ownership, management, and profit distribution. Template available from your state bar or legal service.
  5. Open a business bank account. Most banks require Articles of Organization and EIN.
  6. File Form 2553 to elect S-Corp status. File within 2 months and 15 days of the LLC formation date (or by March 15th for the prior tax year retroactive election). Free to file.
  7. Set up payroll. Gusto ($46/month base), QuickBooks Payroll, or ADP. Required to pay your W-2 salary as an S-Corp owner-employee.
  8. Hire a CPA familiar with S-Corps. Essential for compliant filing of Form 1120-S annually.

Total setup cost: $150–$700 in state fees + $49–$149 for online formation service (optional). Ongoing accounting: $1,500–$3,000/year.

UK: Forming a Limited Company

  1. Register on Companies House. Gov.uk offers online registration for £12 (same-day if filed before 3pm). Choose a company name (must be unique), confirm registered address, and appoint directors and shareholders.
  2. Register for corporation tax with HMRC. Must be done within 3 months of starting to trade.
  3. Open a business bank account. Required for a limited company. Many banks require 2–4 weeks for approval; Tide, Starling, or Revolut Business offer faster digital-first account opening.
  4. Register for VAT if turnover will exceed £90,000/year.
  5. Hire a UK accountant. Essential for preparing statutory accounts, filing Corporation Tax Return (CT600), running payroll for director salary, and managing Self Assessment for dividends.

Total setup cost: £12 + accounting setup. Ongoing: £1,000–£2,500/year for accountant.

Australia: Forming a Pty Ltd

  1. Register for ABN (Australian Business Number). Free at abr.gov.au. Essential for all business income.
  2. Register the company with ASIC. Australian Securities and Investments Commission registration for a Pty Ltd costs $538 (2024 fee). Can be done through ASIC Connect or via a business registration service.
  3. Register for GST if annual turnover will exceed $75,000.
  4. Open a business bank account. Required by all major banks for company accounts (typically requires Certificate of Incorporation and company constitution).
  5. Appoint a registered agent or maintain a registered office. Required by ASIC.
  6. Hire a registered tax agent or accountant. Required for compliant company tax returns and ASIC annual review compliance.

Total setup cost: $538 ASIC fee + formation services. Ongoing: $2,000–$4,000/year for accountant and ASIC annual review.

Common Structural Mistakes

Operating as a sole proprietor well beyond the income threshold. At $80,000–$100,000+ in net consulting income, sole proprietor or default LLC status costs $5,000–$15,000 more in taxes annually compared to optimal structure. Many consultants delay incorporation for simplicity and pay the difference for years.

Not maintaining proper corporate formalities. An LLC or limited company that does not maintain separate finances, keep records, and comply with filing requirements can have its liability protection challenged in court.

Setting S-Corp salary too low. Taking a $20,000 salary on $200,000 in business income is a red flag for IRS audit. Pay a salary that a reasonable employer would pay for your role and experience.

Incorporating too early. A consultant at $25,000/year in profit does not need an S-Corp. The additional accounting costs may exceed the tax savings. Use the income thresholds in this guide as a starting point, then confirm with an accountant.

Not understanding VAT/GST obligations. UK consultants billing over £90,000/year must register for VAT. Australian consultants over $75,000 must register for GST. Missing registration creates penalties and backdated liability.

DIY without professional advice for your specific situation. This guide provides a framework. Your specific marital status, state of residence, income level, retirement planning, and future growth plans affect which structure is optimal. A one-hour consultation with a CPA or tax advisor costs $200–$500 and typically saves multiples in the first year.