How should solicitors account for client interest on mixed funds?

At Towerstone Accountants we provide specialist accountancy services for solicitors and law firms operating under SRA regulation. This article has been written to explain How should solicitors account for client interest on mixed funds in clear practical terms so you understand how the rules apply in day to day practice. Our aim is to help you stay compliant protect client money and make informed financial decisions.

Client interest on mixed funds is one of those topics that rarely feels urgent until it suddenly becomes a problem. Many solicitors assume interest is negligible or that banks deal with it automatically. In reality how interest is calculated allocated and recorded is an important compliance issue and one that can expose firms to complaints or regulatory scrutiny if handled poorly.

I often see firms that are otherwise well run fall short here not through bad intent but because the rules feel technical and interest amounts seem small. The challenge is that client interest is not about materiality alone. It is about fairness transparency and trust. The SRA expects firms to have a clear policy and to apply it consistently.

In this article I will explain how solicitors should account for client interest on mixed funds in a practical and understandable way. I will cover what mixed funds are how interest arises what the rules expect how interest should be calculated and recorded and where firms commonly go wrong. This is based on current UK regulatory guidance and real world experience advising law firms.

What are mixed funds in a client account

Mixed funds arise when money belonging to more than one client is held together in a single client account. This is extremely common. Most firms operate a general client account rather than a separate bank account for each client.

Within that account there may be:

• Multiple client balances held at the same time
• Money received at different dates
• Funds held for different purposes and time periods

The bank pays interest on the total balance in the client account rather than on individual client ledgers. This creates the need for a fair method of allocating interest between clients.

Why client interest matters even when amounts are small

It is tempting to dismiss interest as immaterial particularly in a low interest environment. That mindset is risky.

Client interest matters because:

• It belongs to the client not the firm
• It reflects the firm’s fiduciary duty
• It can become significant over long periods
• Complaints often arise on principle not value

Even small amounts can lead to reputational damage if clients feel they have been treated unfairly.

The regulatory framework for client interest

The handling of client interest is governed by the Accounts Rules issued by the Solicitors Regulation Authority.

The core principle is straightforward. Clients are entitled to a fair sum of interest on money held on their behalf unless it is fair to retain it.

The rules do not prescribe a single calculation method. Instead they require firms to act fairly and to have a written policy that explains how interest is dealt with.

This flexibility increases responsibility. Firms must be able to justify their approach if challenged.

What the SRA expects in practice

From a practical perspective the SRA expects firms to:

• Consider whether interest should be paid to clients
• Have a clear written client interest policy
• Apply that policy consistently
• Account for interest accurately where due
• Explain the policy to clients

The emphasis is on fairness rather than mathematical perfection.

Understanding when interest is payable to clients

Interest is generally payable where client money is held for a period of time and generates a meaningful benefit.

Factors that influence whether interest should be paid include:

• The amount of money held
• The length of time it is held
• The interest rate environment
• The administrative cost of calculation
• What the client has been told in advance

Short term balances held briefly may not justify payment. Larger sums held for months or years almost always do.

Mixed funds and the challenge of allocation

With mixed funds the bank pays interest on the total balance not on individual client amounts. The firm must then decide how to allocate that interest.

The challenge is ensuring that:

• Clients are treated equitably
• No client subsidises another unfairly
• The firm does not benefit improperly

This requires a rational and documented approach.

Common approaches to allocating interest on mixed funds

There are several accepted methods for allocating interest. The key is consistency and fairness.

Common approaches include:

• Pro rata based on balances and time held
• Threshold based policies
• De minimis policies
• Separate designated deposit accounts for large sums

Each approach has advantages and drawbacks.

Pro rata allocation explained

A pro rata approach allocates interest based on:

• The amount of money held for each client
• The length of time it was held

This is the most precise method but also the most administratively demanding.

It requires:

• Accurate client ledger balances
• Clear records of dates
• Regular calculations

Many larger firms use this approach supported by accounting software.

Threshold or de minimis policies

Many firms adopt a threshold policy.

Under this approach interest is only paid where:

• A minimum balance is exceeded
• Funds are held for longer than a stated period

For example a firm may decide that interest is only paid where more than a set amount is held for more than a certain number of days.

This approach is permitted provided it is fair transparent and clearly communicated.

Separate designated deposit accounts

For large sums held for long periods such as probate or property transactions firms may place funds in a separate designated deposit account.

In this case:

• Interest earned is clearly attributable to that client
• Allocation is straightforward
• Transparency is high

This approach is often the cleanest for significant balances.

Why the firm must not profit from client interest

One of the most important principles is that the firm must not profit from client money.

If interest is retained by the firm it must be because:

• It is fair to do so
• The amount is genuinely minimal
• The administrative cost would exceed the benefit
• The client has been informed

Using retained interest to subsidise general costs without justification is a breach of trust.

The role of the client interest policy

Every firm that holds client money should have a written client interest policy.

This policy should explain:

• When interest will be paid
• How it will be calculated
• Any thresholds or exclusions
• How interest is credited or paid
• Where the policy is communicated to clients

The policy is the firm’s first line of defence if questioned.

Communicating the policy to clients

Transparency is essential.

Clients should be told:

• That their money may earn interest
• Whether they are entitled to receive it
• How the firm’s policy works

This is usually done through engagement letters or terms of business.

Surprises are the root of most complaints.

How interest should be recorded in the accounts

From an accounting perspective interest on client money must be recorded carefully.

Key principles include:

• Interest earned belongs to clients unless justified otherwise
• Client interest should not be treated as firm income
• Client interest liabilities should be tracked

Where interest is payable it should be credited to the relevant client ledger or paid out directly.

Accounting entries in simple terms

Conceptually the accounting reflects:

• Interest received from the bank
• Allocation between clients
• Any retained amounts justified under the policy

Accurate records must show:

• Total interest earned
• How much was allocated
• How much if any was retained
• The basis for retention

This supports both compliance and audit trails.

Timing of interest allocation

Interest should be allocated:

• At appropriate intervals
• When matters conclude
• When funds are returned

Leaving interest unallocated indefinitely is poor practice.

VAT and client interest

Client interest is not subject to VAT when it is paid to the client. It is not consideration for services.

If interest is retained by the firm under a valid policy it is still generally outside the scope of VAT.

Incorrect VAT treatment is uncommon but can arise if interest is misclassified as income.

Reconciliations and interest

Interest must be considered as part of regular client account reconciliations.

Reconciliations help ensure that:

• Interest earned is identified
• Client balances remain accurate
• No unexplained differences exist

Ignoring interest can lead to unexplained variances over time.

Common mistakes firms make with client interest

In practice I see the same issues repeatedly.

These include:

• No written client interest policy
• Assuming interest is too small to matter
• Retaining interest without justification
• Inconsistent treatment between clients
• Poor records of interest earned

These issues are avoidable with clear systems.

Complaints and regulatory risk

Client interest issues often surface through complaints rather than inspections.

Clients may complain when:

• They become aware interest was earned but not paid
• Another firm pays interest and yours does not
• They feel treated unfairly

Even small sums can escalate into regulatory issues if mishandled.

The role of accountants in managing client interest

Accountants play a key role in helping firms manage client interest properly.

This includes:

• Designing fair allocation policies
• Setting up systems to track interest
• Ensuring accounting treatment is correct
• Supporting reconciliations
• Advising on complex or borderline cases

This support reduces risk and administrative burden.

Technology and automation

Modern accounting and practice management systems can automate much of the interest process.

When configured properly they can:

• Track client balances over time
• Calculate pro rata interest
• Produce clear audit trails

Technology is a tool not a substitute for judgement. Policies must still be fair and understood.

What to do if past treatment was incorrect

If a firm identifies that client interest has been mishandled in the past the worst response is inaction.

The correct approach is to:

• Assess the extent of the issue
• Quantify amounts where possible
• Correct records
• Pay interest to clients if required
• Review and update policies

Transparency and prompt action usually reduce regulatory consequences.

My professional view

In my experience client interest on mixed funds is less about arithmetic and more about mindset.

Firms that approach it with fairness clarity and transparency rarely encounter problems. Firms that ignore it because amounts feel small often end up dealing with complaints that cost far more in time stress and reputation.

The rules allow flexibility but that flexibility must be used responsibly.

Final thoughts

Accounting for client interest on mixed funds is an essential part of holding client money properly.

Solicitors should ensure they have a clear written policy that explains when interest is paid how it is calculated and how it is recorded. That policy should be communicated to clients and applied consistently.

With good systems regular reconciliations and professional oversight firms can manage client interest confidently and compliantly. Done well it reinforces trust and demonstrates the financial integrity expected of a regulated legal practice.

You may also find our guidance on How can accountants help solicitors manage client interest and How often should solicitors reconcile their client account useful when reviewing related SRA and accounting obligations. For a broader overview of solicitor accounting and compliance topics you can visit our solicitors accounts rules hub which brings all related guidance together.