Bad Debts at Your Agency: Writing Them Off and Claiming Tax Relief

Key takeaways

• Bad debts are a normal part of agency business – you need a clear process for identifying and dealing with unpaid invoices that won't be collected.
• Writing off a bad debt is a formal accounting step – it removes the unpaid amount from your sales ledger and reduces your reported profit for tax purposes.
• You can claim tax relief on bad debts – this reduces your Corporation Tax bill, effectively giving you back some of the money you lost.
• Timing and evidence are crucial – you must write off the debt in the correct accounting period and keep records proving you've taken reasonable steps to collect it.
• Good client onboarding and credit control prevent bad debts – the best strategy is to stop them happening in the first place.

What are bad debts for an agency?

Bad debts are invoices you've issued to clients that you now believe you will never be paid for. For a marketing or creative agency, this usually means a client has gone silent, gone bust, or is outright refusing to pay for work you've already delivered. The money you recorded as income (your sales) never actually arrives in your bank account.

This creates a problem for your accounts and your tax. Your profit, which you pay tax on, includes all the sales you've invoiced. If a £10,000 invoice is never paid, your real profit is £10,000 less than your accounts show. A bad debt write off fixes this mismatch. It's an accounting adjustment that says, "We're not expecting this money anymore, so let's remove it from our sales figures."

It's different from an overdue invoice you're still chasing. A debt only becomes "bad" when you have solid evidence that further collection efforts are pointless. Common signs for agencies include a client entering liquidation, a statutory demand being ignored, or a client disappearing entirely after multiple contact attempts.

Why is managing bad debts so important for agencies?

Managing bad debts is critical because it directly protects your agency's cash flow and accurate profit reporting. Unpaid invoices tie up the money you've already spent on team salaries, freelancer costs, and software to deliver the work. Writing them off correctly ensures your financial statements show the true health of your business and that you don't overpay tax on income you never received.

For agency owners, the impact is twofold. First, your cash flow takes a direct hit. You've paid your team to do the work but have no client money coming in to cover it. Second, if you don't write off the debt, you'll pay Corporation Tax on that phantom income. On a £15,000 bad debt, at a 25% tax rate, that's an unnecessary £3,750 tax payment on money you never had.

Furthermore, consistently high bad debts are a warning sign. They can point to weak client onboarding, poor credit control processes, or pricing clients who are a bad financial fit. In our experience working with agencies, those with a formal process for assessing and writing off bad debts also tend to have stronger overall financial discipline.

When should you write off a bad debt at your agency?

You should write off a bad debt when you have reasonable evidence that you cannot recover the money, and you make a formal business decision to stop pursuing it. There's no fixed timeline, but common triggers include a client company going into administration, a debt being over 6-12 months old with no payment plan, or legal advice confirming recovery costs would exceed the debt.

The key is "reasonable evidence." HMRC expects you to have tried to collect the debt. For agencies, this means keeping records of your chase emails, final demand letters, and any responses (or lack thereof). You can't just decide a debt is bad because it's inconvenient. You need to show you've taken commercial steps to get paid.

Timing is also crucial for tax. You must write off the debt in the accounting period where you identify it as irrecoverable. If you realise in March that a debt from last September is bad, you write it off in your March year-end accounts. You can't go back and amend old tax returns for debts you later write off.

How do you actually write off a bad debt?

Writing off a bad debt is a two-step process: a commercial decision followed by an accounting entry. First, you need internal approval, often from a director or finance lead, confirming the debt is uncollectable. Document this decision with the evidence (e.g., "Client Ltd entered liquidation on X date, per Gazette notice"). Then, your accountant or bookkeeper makes the journal entry in your software to remove the debt.

The accounting entry reduces your sales (debtors) and reduces your profit. If you use accruals accounting, which most agencies do, the entry credits your debtors ledger and debits an expense account called "Bad Debts Written Off." This expense then flows through to your profit and loss account, lowering your taxable profit.

It's vital to keep the invoice and all correspondence in your records. HMRC may ask to see proof that the debt was genuine and that your write-off was justified. A clear paper trail showing the work was delivered, the invoice was issued, and collection was attempted is your best defence. Using accounting software like Xero or QuickBooks makes tracking and documenting this much easier.

How does bad debt tax relief work for agencies?

Bad debt tax relief works by reducing your agency's taxable profit by the amount of the written-off debt. When you write off a £5,000 invoice as bad, you add a £5,000 expense to your accounts. This lowers your profit before tax by £5,000. You then pay Corporation Tax on this lower profit figure, saving you the tax you would have paid on that lost income.

Here's a simple example. Your agency makes £200,000 in sales (invoiced). You write off £8,000 in bad debts. Your taxable sales become £192,000. If your profit margin is 20%, your profit before tax drops from £40,000 to £32,000. At the 25% Corporation Tax rate, your tax bill falls from £10,000 to £8,000. The tax relief has given you back £2,000 of the £8,000 you lost.

The relief is automatic if you correctly record the write-off in your statutory accounts and tax computation. You don't need to make a separate claim to HMRC. However, the debt must have been included in your sales figures in the first place. You can't claim relief on a deposit you never invoiced for or on speculative work. The official guidance on this is covered under HMRC's Business Income Manual (BIM42701).

What records do you need to keep for a bad debt write off?

You need to keep records that prove the debt existed, the work was done, and you tried to collect it. This includes the original signed contract or statement of work, the issued invoice, proof of delivery (emails sending final assets, project management completion notes), and a full audit trail of your collection efforts.

Your collection trail should show escalating steps. Keep copies of the invoice payment reminders, follow-up emails, final demand letters sent by recorded delivery, and any responses. If you used a debt collection agency or sought legal advice, keep that correspondence too. For a client that has become insolvent, keep the notice from The Gazette or the insolvency practitioner.

These records are not just for HMRC. They help you analyse why the bad debt occurred. Was the client undercapitalised from the start? Did scope creep lead to a dispute? Good records turn a financial loss into a learning opportunity to tighten your client agreements and payment terms. Many agencies we work with add a clause about debt recovery costs to their contracts after experiencing a bad debt.

Can you claim VAT back on a bad debt?

Yes, you can often claim back the VAT you paid to HMRC on a bad debt, but only if you use standard VAT accounting and the debt is at least 6 months overdue. This is called "Bad Debt Relief" for VAT. You must have already accounted for and paid the VAT on the invoice to HMRC. You then reclaim it by adjusting your next VAT return.

The rules are specific. The invoice must be more than 6 months past its due date. You must have written off the debt in your day-to-day VAT accounts and transferred it to a separate bad debt account. You also need to keep the same detailed records as for the income tax relief. The VAT Notice 700/18 explains the full process.

For many small agencies on the Flat Rate VAT scheme, the situation is different. You generally cannot claim bad debt relief under this scheme because you pay VAT as a percentage of your total sales, not on each individual invoice. This is an important consideration when choosing or reviewing your VAT scheme, as bad debts pose a greater cash flow risk if you can't reclaim the VAT.

How can agencies prevent bad debts in the first place?

The best way to handle bad debts is to stop them happening. This starts with robust client onboarding and clear payment terms. Always conduct basic due diligence on new clients. For larger retainers or projects, consider a credit check. Have a standard contract that includes clear payment terms, late payment interest, and states that you retain ownership of work until fully paid.

Implement strong financial operations. Use deposit payments for new projects, especially with new clients. Break large projects into phased payments tied to deliverables. Send invoices promptly and use automated payment reminders. Have a clear process for when an invoice becomes 30, 60, and 90 days overdue, including pausing work if necessary.

Your commercial mindset matters too. Be wary of clients who constantly question your value or try to negotiate your rates down aggressively. They are often the most likely to delay or refuse payment later. It's better to have fewer clients who pay well and on time than many who are a constant collection headache. Taking our free Agency Profit Score can help you identify weaknesses in your financial controls that might be exposing you to bad debt risk.

What are the common mistakes agencies make with bad debts?

The most common mistake is doing nothing – leaving old, unpaid invoices sitting on the balance sheet as "debtors" year after year. This overstates your assets, misleads you about your financial health, and causes you to overpay tax. Another error is writing off debts too casually without proper evidence, which could be challenged by HMRC.

Agencies also often forget to reclaim the VAT on bad debts that qualify. This is literally leaving cash on the table. Conversely, some try to claim tax relief on deposits or upfront payments they never actually invoiced for, which is not allowed. The debt must have been recorded as income in your accounts.

Finally, many agencies treat bad debts as purely an accounting problem, not a commercial one. They don't review why the debt went bad and fail to update their client onboarding or contracting processes to prevent a repeat. Every bad debt should trigger a review of your financial operations. Specialist accountants for digital marketing agencies can help you set up these preventative systems.

When should you get professional help with bad debts?

You should consider professional help if you have multiple or large bad debts, if you're unsure about the correct accounting or tax treatment, or if you need to improve your systems to prevent future issues. An accountant can ensure your write-offs are compliant and maximise your tax relief. They can also review your contracts and payment processes.

If a debt is large and the client is refusing to pay but is still trading, it may be worth consulting a solicitor before writing it off. Sometimes a legal letter is enough to secure payment. A debt collection agency may also be an option for larger sums, though they will take a percentage of what they recover.

Ultimately, consistent bad debts are a symptom of deeper financial management issues. If you're frequently writing off invoices, it's a sign to get expert help. A proactive, commercial CFO or accountant can help you build a more financially resilient agency. Start by getting a clear picture of your financial health with our free Agency Profit Score.