Most UK merchants think of chargebacks as an annoyance with a price attached: the lost goods, the disputed amount, the fee your provider passes on. That framing is now out of date. Since 1 April 2026 Visa has run its Acquirer Monitoring Programme (VAMP) with a tighter excessive merchant threshold of 1.5%, down from 2.2%, and the practical effect is that a dispute ratio which looked survivable last year can now put your ability to accept cards at all under review. If you sell online, this is worth half an hour of your time this week.

What actually changed in April

VAMP replaced Visa's two older schemes, the Dispute Monitoring Programme and the Fraud Monitoring Programme, with a single combined measure. Rather than tracking fraud and disputes separately, VAMP adds TC40 fraud reports and TC15 dispute records together and divides the total by your settled card-not-present transactions. One ratio, one threshold, one enforcement track.

The number that moved in April was the merchant-level excessive threshold, cut to 1.5% for merchants in the UK and Europe as well as the US, Canada and Asia-Pacific. There is a volume floor too: you are only enrolled once you exceed both the ratio and roughly 1,500 combined fraud and dispute events in a month, so a small seller with a handful of disputes is not suddenly in scope. Acquirer-level thresholds sit lower still, at 0.5% above standard and 0.7% excessive, which is why your provider watches this more closely than you might expect.

Why the ratio moved even if your fraud did not

Here is the part that catches merchants out. Rising ratios in 2026 are not mostly about criminals. They are about first-party misuse, sometimes called friendly fraud, where a genuine cardholder disputes a genuine purchase. Mastercard's own dispute research puts first-party fraud at more than 45% of all chargebacks, and industry surveys through 2024 and 2025 consistently show it overtaking third-party card fraud as the leading category. Your fraud screening can be working perfectly and your ratio can still climb.

Two things follow. First, tools that block bad transactions at checkout will not fix a first-party problem, because the transaction was legitimate at the point of sale. Second, the fixes that do work are unglamorous and operational:

  • Billing descriptors: a large share of "I don't recognise this" disputes are simply cardholders failing to match a trading name to a purchase. Check what appears on a statement and make it recognisable.
  • Refund friction: if your refund process is slower or harder than calling the bank, customers will choose the bank. A refund costs you the sale; a chargeback costs you the sale, a fee, and a point on the ratio.
  • 3-D Secure 2 coverage: authenticated ecommerce transactions shift liability for a large class of fraud disputes and feed the evidence trail Visa uses for automatic dispute defence.
  • Delivery and usage evidence: retain proof of delivery, IP and device data, and login or consumption records. This is what a compelling evidence submission is built from.
  • Subscription hygiene: clear renewal reminders, easy cancellation, and an accurate free-trial end date remove one of the most common triggers entirely.

The cash-flow arithmetic

Chargebacks are expensive well beyond the disputed amount. Merchant research commonly puts the fully loaded cost at around five times the value of the transaction itself once you count the goods, the fee, the staff time spent representing the case and the acquirer overhead. On top of that sits the ratio risk: enrolment in VAMP can bring per-dispute assessments and, at the far end, acquirer decisions about whether to keep the account. Reserves are the quieter consequence. A provider looking at a rising ratio may hold back a percentage of settlement, and for a business used to next-day settlement, that is a direct hit to working capital rather than a line on a statement.

It is also worth noting what the ratio excludes. Disputes resolved before they become chargebacks, through pre-dispute and rapid-resolution services, do not count against you. Neither do fraud reports that qualify under Visa's Compelling Evidence 3.0 rules. Prevention and early resolution are rewarded twice: once in avoided cost, once in a lower ratio.

What to ask your provider, and how Monek approaches it

The single most useful question to put to your acquirer or gateway this week is simply: what is my current VAMP ratio, and how has it moved over the last six months? Plenty of merchants have never been shown the figure. If your provider cannot produce it quickly, that is informative in itself. Follow it with two more: do you offer pre-dispute alerts or rapid dispute resolution, and what proportion of my ecommerce volume is running through 3-D Secure 2 authentication today?

Monek is an FCA-authorised payment institution (FRN 920628) providing a UK payment gateway and we build reporting on the assumption that merchants should be able to see their own numbers. Disputes and refunds sit in the merchant portal alongside settlement, 3-D Secure 2 is standard on our ecommerce and Pay by Link flows, and the same platform covers Virtual Terminal for phone orders, our free WooCommerce payment gateway plugin, native Xero integration for reconciliation and terminal hire from £25 a month. Processing starts at 0.99% blended, with IC++ pricing available for higher-volume businesses, and settlement is next day. If you would like someone to look at your dispute profile alongside your rates, our team will run a no-obligation comparison and tell you plainly whether your ratio is somewhere you should be worried about.