If you've cleared out a wardrobe onto Vinted or flipped a few bargains on eBay this year, don't be surprised if an envelope from HMRC turns up before autumn. A second round of "nudge letters" is landing on sellers' doormats, and this batch is built on sharper data than the first. Online marketplaces have now sent HMRC two full years of seller information under the digital platform reporting rules, and the tax authority is starting to cross-reference it against who has, and hasn't, filed a Self Assessment return.
None of this means every seller owes tax. Most don't. But the letters are unsettling precisely because they arrive without context — a generic warning about "income from online platforms" next to a specific figure for your account, with no explanation of why HMRC thinks that figure matters. Understanding the actual rules turns a scary letter into a five-minute admin task.
Why HMRC suddenly has your sales data
Since 1 January 2024, UK-based platforms — eBay, Vinted, Etsy, Depop, Airbnb and dozens of smaller marketplaces — have been legally required to collect seller details and report them to HMRC annually, under rules based on the OECD's model reporting framework for digital platforms. The first report, covering 2024 sales, was due by 31 January 2025. The second, covering 2025 activity, landed by 31 January 2026. That means HMRC is now sitting on two consecutive years of matched data for anyone who sold regularly through a UK platform, including account names, bank details and total transaction values.
This is not a new tax. Selling personal possessions has never been taxable, and it still isn't. What's changed is visibility — HMRC can now see volume and frequency at a scale it never could when everything ran through cash, PayPal transfers and word of mouth. A seller doing thirty transactions a month on Vinted used to be invisible to the tax system. Now they show up in a spreadsheet next to their National Insurance number.
The £1,000 trading allowance, and where it stops helping you
Every individual gets a trading allowance of £1,000 a year, covering gross income from self-employment-style activity before any expenses are deducted. Sell under that in a tax year and you generally don't need to register for Self Assessment or declare anything, regardless of what a platform reports to HMRC. Sell over it, and the calculation changes: you either claim the £1,000 allowance against your income (simple, but you lose the ability to deduct actual costs) or you deduct your genuine expenses instead — postage, packaging, platform fees, the original cost of stock you bought to resell. Whichever leaves you with a lower taxable profit is the better choice, and there's no penalty for switching between tax years as your circumstances change.
Here's where people trip up: the £1,000 threshold is based on gross sales income, not profit, and not the amount a platform actually pays out after its own fees. If eBay's records show £1,400 in buyer payments across the year, that's the figure against the allowance — not the £1,150 that landed in your bank account after eBay's cut.
Badges of trade — clearing a wardrobe versus running a shop
The harder question, and the one HMRC's own guidance leans on heavily, is whether what you're doing counts as trading at all. HMRC uses a long-standing set of tests known as the "badges of trade" — frequency of transactions, whether items were bought specifically to resell, whether you modified or improved goods before selling, and how organised the activity looks. Selling your own old clothes, a bike you no longer use, or furniture from a house move is disposal of personal possessions, full stop, no matter how many items or how much money changes hands. Buying stock at car boot sales specifically to resell on Vinted at a markup is trading, even if you only do it at weekends and never register a business name.
The distinction matters because it decides which allowance applies. Personal possession sales aren't trading income at all, so the £1,000 trading allowance is irrelevant — though Capital Gains Tax can occasionally apply to individual items worth over £6,000, which rarely comes up for clothes and furniture but does for jewellery, art or collectibles. Trading income, by contrast, sits squarely inside the rules above.
What to actually do if a letter arrives
Read it properly before reacting. HMRC's nudge letters are not tax demands — they're a prompt to check your position and come forward voluntarily if you owe something, and treating one that way rather than as an accusation changes the whole tone of your response. If your sales genuinely were personal possessions, keep a short note of what you sold and why (a house move, a decluttering session, items inherited from a relative) in case HMRC follows up, but you don't owe anything and don't need to file.
If you were trading and crossed £1,000 in gross sales in a tax year you haven't declared, register for Self Assessment. The deadline is 5 October following the end of the tax year in which you became liable — so for the 2025/26 tax year, that's 5 October 2026. Miss it and HMRC can charge a failure-to-notify penalty on top of the tax owed, though penalties are markedly lower for unprompted disclosure than for cases HMRC has to chase. Registering because you read a nudge letter and acted on it counts as coming forward — waiting for a formal enquiry letter does not.
The record-keeping habit worth building now
Whichever category you fall into, start keeping proper records from your next sale onward. Export your transaction history from each platform every few months rather than relying on memory a year later, and keep receipts for anything bought as stock. Under Making Tax Digital for Income Tax, sole traders and landlords above the relevant income threshold now need to keep digital records and submit quarterly updates rather than a single annual return — a habit that's far easier to build gradually than to retrofit under deadline pressure. A shoebox of Vinted printouts from March won't cut it when your accountant asks for numbers in January.