A gilt purchase that settles below its quoted price can look like a small bargain. During the ex-dividend period, however, the deduction accompanies a missing cash flow: the next coupon belongs to the seller, so a yield calculation that credits it to the buyer overstates the return.[1]

The revealing number on the contract note is negative accrued interest. It does not mean the government has imposed a negative interest rate. It means the buyer receives part of the period's interest through a smaller purchase payment, rather than through the imminent coupon. Following that deduction explains both why the bill falls and why buying just before payment day creates no automatic windfall.[5]

The payment has an earlier owner

For gilts, the register is checked at the close of business seven business days before the payment date. A purchase settling on that record date still carries entitlement; one settling afterward does not. The relevant clock is settlement, when the transaction completes, rather than the moment someone presses Buy.[1]

The distinction matters around a weekend or bank holiday. The DMO describes normal gilt-market settlement as the next business day after trading. A trade executed on the record date can therefore settle too late to acquire the approaching coupon. The trade date, settlement date and payment date are separate fields for a reason.[4]

Once the entitlement has stayed with the seller, the accounting has to compensate the buyer for the short interval between taking ownership and the coupon date. That compensation is called rebate interest. It usually appears as a deduction from the amount paid.[1]

Reconstructing the smaller bill

FTSE Russell's calculation guide illustrates the convention with a conventional gilt paying a 6% annual coupon, split between March and September. Its example settles on September 1, six calendar days before the September 7 coupon, within a coupon period lasting 184 days.[2]

Scale that example to £10,000 face value and assume a clean quote of 100, meaning the face amount costs £10,000 before the interest adjustment. This is an illustrative quote, not a live security recommendation. Assume a normal coupon period, maturity beyond the following March, and no dealing fees or taxes.

The semiannual coupon is £300. The buyer's rebate covers only the six remaining days:

Rebate interest = £300 × 6 ÷ 184 = £9.7826…

Applied as negative accrued interest, that produces this settlement calculation, rounded to pennies:[2][3]

The buyer receives no coupon on September 7. The seller receives the full £300, having effectively passed the buyer's share back through the sale price. If the buyer remains entitled at the following March record date, that later coupon belongs to the buyer.[2]

Why does losing an entire coupon produce such a small deduction? Because the starting figure is the clean quote. It already excludes accrued interest. A purchase carrying the September coupon would normally require an additional payment for the seller's accumulated interest. The ex-dividend buyer avoids that positive accrual as well as receiving the small rebate. Comparing settlement cash with the clean quote alone hides the larger change in entitlement.[3]

Value only the cash that arrives

The DMO's conventional-gilt pricing formula makes the entitlement change explicit: when settlement occurs in the ex-dividend period, the next coupon term is set to zero. The remaining coupons and redemption payment still enter the valuation. The dirty price—the price including accrued interest—is the cash value to reconcile with that payment stream.[3]

That gives a practical way to audit a spreadsheet. Start with the settlement outflow, omit the September coupon, then discount the payments the buyer actually owns. A model that enters the reduced outflow but retains the missing coupon invents value. A model that deducts the rebate again after using the dirty price counts the same benefit twice.

The worked example deliberately stops short of quoting a redemption yield. Without a maturity date and the complete remaining schedule, that figure cannot be calculated. The coupon rate describes the contractual interest on face value; it cannot fill in the missing valuation inputs.

A genuine bargain can still exist

The strongest counterweight is that coupon mechanics do not explain every price difference. Market yields and dealing spreads can change while the entitlement clock advances. A gilt bought during its ex-dividend period may offer attractive value for independent reasons. The deduction merely fails to establish that case by itself.[4]

The falsifier for applying the rebate explanation to a particular purchase is a confirmation showing settlement on or before the record date, with the approaching coupon included. That purchase has not lost the payment, so a smaller debit needs another explanation. Check the quantity, quoted price, interest line and charges before attributing the difference to valuation.[4]

Tax adds another boundary. HMRC's Accrued Income Scheme can treat the buyer's rebate as income even though it arrived as a reduction in purchase cost. Where the scheme applies, the absence of a bank-account coupon does not establish the absence of taxable interest.[5]

Three dates to watch

• When the trade confirmation arrives: compare its settlement date with the registrar's record date. That establishes which coupon schedule the valuation must use.[1][4]
• At the September payment in the illustration: reconcile the missing coupon with the rebate already received through settlement. An unexpected receipt calls for checking entitlement and any broker adjustment, not immediately annualizing a windfall.
• At the following March payment: assuming continued ownership through its record date, check the first coupon actually received against the cash-flow schedule used at purchase. The investment's return depends on that full schedule and its purchase cost, not on the attractive minus sign on one line.

Sources

1. UK Debt Management Office, “About Gilts” — issuer, record-date boundary, settlement-based entitlement and rebate interest.
2. FTSE Russell, Guide to the Calculation Methods of the FTSE Actuaries UK Gilts Index Series, version 3.9, April 2026, Appendix A, pages 41–42 — actual-day accrual and the September ex-dividend example.
3. UK Debt Management Office, Formulae for Calculating Gilt Prices from Yields, sections 1 and 3 — conventional-gilt cash-flow valuation, coupon exclusion and accrued-interest formulas.
4. UK Debt Management Office, “Glossary” — clean and dirty prices, normal gilt settlement, the ex-dividend period and dealing spreads.
5. HM Revenue & Customs, Savings and Investment Manual, SAIM4020 — treatment of cum-dividend and ex-dividend transfers under the Accrued Income Scheme.
6. Tilman2007, “New Government Offices (HM Treasury) and archway link with Foreign Office at east end of King Charles Street,” August 20, 2023, Wikimedia Commons — photograph and attribution, CC BY-SA 4.0.