The Unclaimed Margin: Pricing Voucher Breakage Into UK Direct Mail Plans

A money-off voucher is a promise with a deadline. When the deadline passes, finance teams tend to see a tidy gain: the discount was budgeted, the voucher was not used, and the campaign lands ahead of plan. That reading is tempting, and often wrong. In direct mail, breakage is not a single number. It is the residue of several different behaviours, only some of which represent commercial success.

For UK advertisers planning 2026 mailpacks, the task is to price breakage deliberately rather than celebrate it after the fact. That means separating response from redemption, treating outstanding vouchers as a liability until they expire, and asking whether non-redemption reflects a customer who chose not to buy or a customer who bought without the voucher.

Separate response from redemption

Many campaign reports collapse several measures into one redemption figure. That is a mistake. A useful breakage budget starts with four distinct measures: response rate, redemption rate among responders, leakage and expiry breakage.

Response rate is the proportion of recipients who buy within the campaign window, whether or not they use the voucher. Redemption rate among responders is the proportion of those buyers who present the voucher. Leakage is the proportion of buyers who were eligible but paid without using the voucher, perhaps because the voucher was lost, misunderstood or deemed unattractive. Expiry breakage is the proportion of issued vouchers that remain unredeemed when the expiry date passes.

A low redemption rate can therefore mean several things. It may indicate healthy breakage if sales are strong and customers would have bought anyway. It may indicate leakage if customers are buying but not bothering with the voucher. It may also indicate failure if recipients are not buying at all. Only the first of those is a comfortable result.

A four-line model for 2026 planning

The simplest way to price breakage into a campaign plan is to build a contribution model with four lines. First, set the issued volume and the fixed cost of print, postage and data. Second, forecast response as a range, not a point estimate, and attach an average order value. Third, estimate redemption among responders, the discount depth and any handling cost per redeemed voucher. Fourth, reserve an outstanding liability for vouchers that have not yet expired.

The commercial question is not how much discount was avoided. It is whether the campaign generated incremental contribution after the discount that was actually taken. A voucher campaign with high breakage and weak sales has not saved money; it has spent media and postage to learn that the proposition did not persuade. A campaign with lower breakage and strong sales may be far healthier, even if the discount bill is higher.

A practical planning table helps. High response with high redemption usually signals a strong offer that is costing money but working. Low response with low redemption usually signals a failed mailpack, not breakage. High response with low redemption points to leakage: buyers are present, but the voucher is not doing its job. Low response with high redemption describes a niche offer that converts its small audience efficiently, but may not justify the reach.

The outstanding liability ledger

A voucher that has not expired is not breakage. It is an open obligation. UK advertisers should carry an outstanding liability reserve from the mail date until the expiry date and any claims window has closed. The reserve should be reconciled against redemptions at regular intervals, with a clear owner in finance or commercial operations.

This ledger matters for two reasons. First, it prevents early campaign reports from flattering performance before the liability has cleared. Second, it exposes slow redemption patterns. If redemptions arrive in a burst and then stop, the expiry terms are probably clear. If they trickle in unpredictably, the terms, the code delivery or the customer journey may need review.

Expiry terms should be prominent, reasonable and consistent across the mailpack, the voucher itself and any online landing page. Short expiry windows can suppress response if customers feel rushed or misled. Long windows extend the liability period and complicate reconciliation. The right answer is not a legal minimum but a commercial one: enough time for a genuine customer to act, and enough clarity for the finance team to close the book.

Healthy breakage versus a failed mailpack

Healthy breakage has a commercial logic. It occurs when recipients who would have bought anyway do not use the voucher, or when low-propensity recipients decline the offer without imposing a discount cost. In both cases, the campaign still needs to show that sales would not have happened without the mailpack. Without a control group or a credible pre-period comparison, that claim is difficult to defend.

Unhealthy breakage looks similar in a spreadsheet but behaves differently in the market. It is accompanied by low response, weak average order values or a high proportion of recipients who never engage. In that case, the voucher has not been left unclaimed because the campaign was efficient. It has been left unclaimed because the mailpack did not persuade anyone to act.

The distinction matters for 2026 budget conversations. A marketer who reports high breakage as a success may be rewarded for a campaign that failed to generate demand. A marketer who reports lower breakage but stronger incremental contribution may be penalised for a campaign that worked. The measurement framework should reward the latter.

Fraud controls and expiry discipline

Breakage assumptions are only useful if the redemption population is genuine. UK advertisers should use unique, single-use codes where the mechanic allows, cap redemptions per customer and validate codes at the point of sale or in the fulfilment system. Redemption velocity by postcode sector, device or customer account can reveal clustering that warrants investigation.

Clear terms and conditions are part of the control set. They should state the expiry date, the qualifying products, the exclusions and the redemption channel without ambiguity. Staff at the till or contact centre need the same information as the customer. Fraud controls should not be so heavy that they suppress legitimate redemption, but they should be strong enough to stop a single code being circulated widely.

Pricing breakage into 2026 plans

The practical recommendation is to plan breakage as a range and stress-test the low end. If the campaign only works when a high proportion of vouchers go unused, it is probably not a robust campaign. Build the base case on conservative response and redemption assumptions, then show the finance team what happens if redemption is ten percentage points higher than forecast.

Track actual redemption against the forecast after expiry, not at the mail date. Compare responders with non-responders and, where possible, use a holdout to estimate incrementality. The breakage budget should be a living document, not a post-campaign excuse.

Unredeemed vouchers can be a legitimate margin benefit. They can also be a hiding place for weak creative, poor targeting and loose measurement. The difference is not visible in the breakage rate alone. It is visible in the sales, the liability ledger and the discipline of the assumptions behind them.