Before the Coupon Lands: A Sterling Credit Audit for UK Investors

The search for income has a familiar rhythm. When cash rates ease, UK investors begin to look further along the risk curve, and in 2026 the listed sterling corporate bond market is receiving more attention than it has for some time. The attraction is understandable: a bond carrying a 5% coupon appears to offer a clear and contractually stated income stream. Yet the coupon is only the opening line of the return calculation. For a retail portfolio, the relevant question is not what the bond promises to pay each year, but what the investor actually receives after price, accrued interest, issuer options, duration and dealing costs are taken into account.

Clean, dirty and the cash that is not yours

A listed bond is usually quoted on a clean price, meaning the price excludes interest that has accrued since the last coupon date. The investor pays the dirty price: clean price plus accrued interest. This distinction matters because accrued interest is not a gain. It is a return of cash that the seller has earned but not yet received.

Take an illustrative sterling bond with a 5% annual coupon paid semi-annually, a £100 nominal value and a clean price of 98. Assume settlement occurs 60 days after the last coupon date. The half-yearly coupon is £2.50 per £100 nominal. Accrued interest is approximately £2.50 multiplied by 60 divided by 182.5, or roughly £0.82. The dirty price is therefore about 98.82. For £10,000 nominal, the investor pays approximately £9,882, not £9,800.

The next coupon of £250 will include that £82 of accrued interest. Economically, £82 is capital coming back, not income earned during the new holding period. Investors who compare the headline coupon with the cash paid at settlement without adjusting for accrued interest will overstate the running yield. The same principle applies when a bond is bought close to a coupon date: the dirty price rises, but the first coupon payment is correspondingly larger and less rewarding than it appears.

The issuer's option is your risk

Many sterling corporate bonds contain call features. These allow the issuer to redeem the bond early, typically at par or at a modest premium, if refinancing becomes cheaper or if the company's circumstances change. A call is valuable to the issuer and a risk to the investor. If a high-coupon bond is called when rates have fallen, the holder receives par back and must reinvest in a lower-yield environment.

A quoted yield to maturity assumes the bond runs to its stated maturity. Where a call exists, the more prudent measure is yield to worst: the lowest yield the investor would receive across the possible redemption dates. For a bond trading above par with an early call, the yield to worst can be materially below the yield to maturity. The prospectus and the platform's bond documentation should be read for call dates, call prices and any special conditions. A headline coupon of 5% on a callable bond may be a less durable income stream than a lower coupon on a non-callable gilt or a diversified fund.

Duration is not a footnote

Duration measures a bond's sensitivity to changes in yields. A longer-dated bond with a low coupon has higher duration, so its price moves more when market yields shift. In a portfolio context, duration is not an abstract statistic. If a bond has a duration of seven years and yields rise by one percentage point, its price can be expected to fall by roughly 7%, before any offsetting income. For an investor who may need to sell before maturity, that is a real risk.

Credit duration matters too. Corporate bonds carry spread duration: the sensitivity of the price to changes in the issuer's credit spread over gilts. A bond can have a modest government-bond duration but still suffer if the market reassesses the issuer's creditworthiness. This is why a long-dated bond from a cyclical company is not a simple substitute for a short-dated gilt, even if their headline yields look similar.

The spread you pay before the first coupon

Listed corporate bonds are less liquid than equities. Many sterling issues trade infrequently, and retail-sized orders may be filled at a visible bid-offer spread that is wider than the headline yield suggests. A spread of 1.5 percentage points on a £10,000 nominal holding costs about £150 at the outset. If the bond is held for five years, that cost is roughly 0.3% a year. If the bond is called after two years, the annualised drag rises to about 0.75%.

That is before platform charges, dealing commissions and any difference between the indicative price shown on screen and the executable price. For thinly traded bonds, investors should request a firm quote and compare it with the mid-price where available. A wide spread is not necessarily a reason to avoid a bond, but it must be included in the yield comparison. A gilt, by contrast, usually trades with a much narrower spread, and a bond fund typically offers daily liquidity at a published net asset value, although it may impose dilution levies or hold cash.

A worked comparison

Assume a listed sterling corporate bond with a 5% coupon, maturity in 2031, a clean price of 98 and a yield to maturity of 5.6% at the mid-price. The bid-offer spread is 1.5 points. After buying at the offer and amortising the spread over five years, the effective annual yield is closer to 5.3% before platform costs. If the bond is callable in 2028 and is redeemed at par, the yield to worst may be lower still, and the spread is amortised over a shorter period.

Now compare a five-year gilt with a gross redemption yield of 4.5% and a spread of 0.05 points. After dealing costs, the gilt yields approximately 4.45%. A sterling corporate bond fund with a distribution yield of 5.3%, an ongoing charge of 0.25% and a 0.1-point dealing spread offers a net yield of around 4.95%, but it has no maturity date and its capital value can fall. The listed bond appears to offer roughly 25 basis points more than the fund and 75 basis points more than the gilt before credit losses. Whether that compensation is adequate depends on the issuer's balance sheet, the call risk and the investor's ability to hold to maturity.

The audit before the income

For UK investors, the practical lesson is to treat the coupon as a starting point, not a conclusion. Check the dirty price and accrued interest. Read the call schedule. Calculate yield to worst as well as yield to maturity. Compare duration and spread duration with the rest of the portfolio. Obtain an executable quote and include the bid-offer spread in the return calculation. Finally, consider the tax wrapper: corporate bond coupons are generally taxed as income outside an ISA or SIPP, while gilts have distinct capital gains treatment. The coupon may be fixed, but the return is not. In 2026, with cash rates easing, that distinction is worth more than a headline yield.