Structural hedge
Definition
The portfolio of instruments actually held to reduce the earnings sensitivity of non-maturity deposits and equity positions to interest rate movements. Typically comprised of net customer fixed rate lending, interest rate derivatives (including macro cashflow and fair value hedges), and securities (HTC and HTC&S).
What This Actually Means
NMDs and equity are the two principal sources of structural interest rate exposure for most retail banks — both are non-contractual, variable rate funding sources whose earnings are directly affected by rate movements. The structural hedge is specifically designed to reduce this sensitivity by converting a portion of the exposure into a fixed rate income stream over a defined horizon.
The hedge is the actual deployed position — not a model or a target. It is built from three components: net customer fixed rate lending (naturally fixed income that offsets variable rate liabilities), interest rate derivatives (swaps and similar instruments that synthetically convert variable rate exposure to fixed), and securities portfolios held at amortised cost (HTC) or fair value through OCI (HTC&S).
Hedge sizing — why it is always less than total NMDs and equity: the volume of the structural hedge is calibrated on the proportion of deposits and equity deemed stable and rate-insensitive, not the total balance. Two haircuts are applied: a stability haircut (removing the portion of deposits considered volatile or likely to migrate) and a beta haircut (reflecting the fact that even stable deposits only partially reprice, so not all of the balance needs to be hedged). The result is that the structural hedge notional will always be materially smaller than the total NMD and equity balance.
The size may be further constrained by resource considerations. Market liquidity can limit the ability to transact large notionals at acceptable prices, particularly at longer maturities. Internally, capital consumption, leverage ratio constraints, or ALCO's financial resource optimisation framework may cap the hedge below its theoretical demand. These constraints should be explicitly tracked so that the gap between demand and actual hedge is understood and owned rather than simply accepted.
Where It Matters
The structural hedge is only as good as the assumptions underpinning it. Its notional size and maturity profile are derived from estimates of the stable, non-rate-sensitive core of the deposit base — which in turn depend on deposit beta assumptions, NMD behavioural profiling, and volume forecasts. If any of these inputs are wrong, the hedge will be either oversized or undersized relative to the true exposure.
Beta convexity and rate environment optimisation: because deposit betas have convexity — they are lower in low rate environments and expand as rates rise — the beta used to size the structural hedge implicitly reflects a particular rate environment. A hedge sized using a low-rate beta will be calibrated for a world where deposits are sticky and pass-through is minimal; the same hedge in a high-rate environment, where the beta has expanded, will be oversized relative to actual deposit behaviour. Conversely, a hedge sized on a high-rate beta will be undersized when rates are low.
A practical design principle: the structural hedge should be calibrated at a minimum on the beta that applies outside of low-rate margin compression — that is, the beta that reflects normal or elevated rate environments where competitive dynamics are active and pass-through is meaningful. This gives a minimum structural hedge size that is robust in the environments where the hedge is most needed. From that floor, ALCO then has the discretion to increase the hedge notional to optimise for low-rate environments — where a larger hedge generates more fixed income to offset compressed asset yields — as a deliberate rate view or earnings stabilisation choice. This two-step framework separates the minimum defensible hedge from the discretionary overlay, making ALCO's rate view explicit and auditable rather than embedded invisibly in the beta assumption.
Hedge duration — the smoothing vs. agility trade-off: the duration of the structural hedge determines how quickly the portfolio reprices as market rates change. A longer average duration provides greater smoothing — the hedge locks in fixed rates further out, reducing the sensitivity of earnings to near-term rate movements and producing more stable NII over time. However, longer duration comes at the cost of agility. Because the hedge amortises more slowly, the bank's ability to reduce the hedge quickly — whether due to deposit attrition, a change in pricing strategy, or a shift in ALCO's rate view — is constrained. Unwinding long-dated positions in a moved market crystallises mark-to-market losses, and if deposits run off faster than the hedge amortises, the bank may find itself over-hedged with diminishing ability to correct it in the short term. The choice of hedge duration is therefore a fundamental strategic decision, balancing earnings stability against the flexibility to respond to changing business conditions.
Going concern vs. run-off tension: the structural hedge is explicitly a going concern tool. It is built on the assumption that deposits are retained and the balance sheet continues — it is designed to stabilise earnings, not to hedge a wind-down. This creates a direct tension with the EVE run-off framework: the hedge profile that is optimal for NII stability may produce EVE sensitivity under run-off assumptions, and the deposit repricing profile used to size the hedge may differ from the run-off profile used in the SOT. Banks need to manage both simultaneously and be able to explain the differences to their regulator.
Accounting treatment: structural hedges are typically designated under fair value hedge accounting (IAS 39 / IFRS 9 macro hedge) to reduce P&L volatility from mark-to-market movements on the swaps. Where hedge accounting is not applied or breaks down, the swap MTM flows through P&L directly, which can create significant reported earnings volatility even when the economic hedge is working as intended.
Rebalancing risk: as deposit volumes, betas, or the rate environment change, the structural hedge needs to be rebalanced. Rebalancing in size in a moved market is costly — restructuring large swap portfolios crystallises losses or gains that would otherwise have accrued over time. The lag between when the hedge becomes misaligned and when it is rebalanced is itself a source of risk.