UK Prop Trading LLPs: Understanding the Salaried Members and Mixed Members Rules#
Several proprietary trading firms in the UK structure themselves as Limited Liability Partnerships (LLPs), with traders joining as members (partners) rather than employees. This structure offers potential tax advantages — but HMRC has specific anti-avoidance rules that can reclassify what looks like partner profit share into employment income. Understanding these rules is essential for any trader considering or already operating within a UK prop trading LLP.
The LLP Structure in Prop Trading#
A typical prop trading LLP operates as follows:
- The firm provides the trading capital, technology infrastructure, and risk management
- Traders join as designated members or ordinary members of the LLP
- Profits are allocated to members according to the LLP agreement — typically a percentage split
- Members are treated as self-employed for tax purposes, filing Self Assessment returns and paying Class 2 and Class 4 National Insurance Contributions (NICs)
The tax advantage over employment is significant: self-employed individuals avoid employer NICs (13.8%) and gain more flexibility in expense deductions.
HMRC's Salaried Members Rules (Section 863A–863G ITTOIA 2005)#
Introduced in Finance Act 2014, the Salaried Members Rules are specifically designed to prevent businesses from disguising employment relationships as LLP memberships. If all three conditions — A, B, and C — are met, the LLP member is treated as an employee for income tax and NIC purposes.
Condition A: Disguised Salary#
The member's profit share is "fixed, or, if variable, variable without reference to the overall profitability of the firm."
In practice, this means:
- A fixed monthly payment regardless of firm performance → Condition A met
- A payment calculated as a percentage of the member's individual trading P&L, without reference to the firm's total profitability → Condition A likely met
- A genuine share of the firm's overall distributable profits → Condition A not met
Many prop firms allocate profits based on individual trader performance — the trader's P&L on their allocated capital. HMRC may argue this is "variable without reference to overall profitability" because it does not depend on how the firm as a whole performs.
Condition B: Lack of Significant Influence#
The member does not have significant influence over the affairs of the LLP.
For most prop trading LLPs, junior and mid-level traders do not sit on management committees, do not approve the firm's risk parameters, and do not participate in strategic decisions. This condition is usually met for all but the most senior partners.
Condition C: Capital Contribution Below 25% of Disguised Salary#
The member's capital contribution to the LLP is less than 25% of their "disguised salary" (the amount determined under Condition A).
If a trader earns an average of £120,000 per year and has contributed only £10,000 in capital to the LLP, Condition C is met (£10,000 < 25% × £120,000 = £30,000).
Consequence: Employment Tax Treatment#
When all three conditions are met, the LLP must:
- Operate PAYE (Pay As You Earn) on the member's profit share
- Deduct employee NICs (8% on earnings between £12,570 and £50,270; 2% above)
- Pay employer NICs (13.8% on earnings above £9,100)
- The member loses self-employed status for that income
Mixed Members Rules (Section 850C ITTOIA 2005)#
The Mixed Members Rules apply when an LLP has both individual members and non-individual members (typically companies controlled by the individual members).
How It Works in Prop Trading#
A trader might structure their LLP membership through a Personal Service Company (PSC):
- Trader forms a limited company
- The company becomes a member of the prop trading LLP
- Profits are allocated to the company at the corporation tax rate (25%) rather than the individual's marginal income tax rate (up to 45%)
HMRC's Response#
The Mixed Members Rules require profits allocated to a non-individual member to be reallocated to the individual if:
- The individual has power to enjoy the profits allocated to the non-individual
- The profit allocation to the non-individual is excessive relative to its contribution
- The arrangement has a main purpose of securing a tax advantage
In most prop trading scenarios, the trader's PSC contributes nothing beyond the trader's own skill — the capital comes from the LLP. HMRC will reallocate the company's profit share back to the individual for income tax purposes.
HMRC Badges of Trade#
Whether a trader's LLP activity constitutes "trading" (taxable as trading income) or "investment" (potentially taxable as capital gains) depends on the Badges of Trade — a set of factors developed through case law:
| Badge | Application to Prop Trading |
|---|---|
| Profit-seeking motive | Always present |
| Frequency of transactions | High — hundreds or thousands per year |
| Length of ownership | Short — positions held minutes to days |
| Circumstances of sale | Deliberate profit-taking, not forced disposal |
| Supplementary work | Active analysis, execution, and risk management |
| Subject matter | Financial instruments (typically indicates trading) |
For prop traders, the badges almost universally point to trading income rather than investment income. This means:
- Income is taxable as trading profits under ITTOIA 2005
- No access to CGT annual exempt amount (£3,000 for 2026–27)
- No access to Business Asset Disposal Relief (10% CGT rate)
Practical Implications for Prop Traders#
Scenario 1: Genuine Partner#
If you have significant influence, meaningful capital at risk, and your profit share genuinely tracks firm-wide profitability:
- Self-employed status likely sustained
- File Self Assessment
- Pay Class 2 (£3.45/week) and Class 4 NICs (6%/2%)
- Deduct trading expenses against profits
Scenario 2: Salaried Member#
If all three conditions are met:
- Treated as employee for tax purposes
- PAYE and NICs operated by the LLP
- Limited expense deduction opportunities
- No Class 4 NIC planning flexibility
Scenario 3: PSC Structure (Mixed Member)#
If profits are routed through a personal company:
- Mixed Member Rules likely reallocate profits to the individual
- Additional IR35 scrutiny from HMRC
- Corporation tax advantage neutralised
Key Takeaways#
- UK prop trading LLPs are subject to HMRC's salaried member rules — meeting conditions A, B, and C triggers employment tax treatment
- Individual trader P&L-based profit allocation may be classified as "disguised salary" under Condition A
- PSC structures within LLPs are caught by the Mixed Members Rules
- Badges of trade analysis confirms prop trading is "trading income" — not eligible for CGT treatment
- Traders should review their LLP agreements with a tax adviser to assess salaried member risk before relying on self-employed tax rates