Pension Funds and Liability-Driven Investing: Funding Promises Without Losing Liquidity

Start with the benefit promise rather than the asset portfolio

A defined-benefit pension arrangement promises benefits under a specified formula, often involving service, salary or agreed payment rules. Its central problem is therefore not simply to maximise an investment account. It must finance a stream of payments whose timing and size depend on the scheme's terms and its members. This differs from a defined-contribution account, where the accumulated assets are central to the individual's eventual resources. Liability-driven investing, usually shortened to LDI, starts with the pension obligations and asks how assets should respond to the financial factors that change their measured value. It does not make every obligation certain or remove the need for contributions and governance. The relevant unit of analysis is the whole scheme: assets, promised benefits, sponsor support and available liquidity. An attractive return in isolation can be insufficient if the liabilities rise faster or the cash is unavailable when required.

Discount rates change present values, not the nominal promise

Consider a deliberately simplified promise to pay 100 monetary units exactly ten years from now. Discounting at 5 percent annually gives a present value of about 61.39; discounting the same payment at 4 percent gives about 67.56. The promised payment remains 100. Only its valuation today changes. Real pension liabilities consist of many expected payments, uncertain survival patterns and potentially inflation-linked benefits, so this example is not a valuation model for an actual scheme. It isolates the inverse relationship between discount rates and present value. The discount basis also matters: accounting, regulatory funding and transaction valuations need not use identical assumptions. IAS 19 addresses an accounting measurement framework, not a universal economic price for every pension promise. Comparisons between schemes or reporting dates should identify the basis before interpreting a funding percentage. A change in assumptions can alter the reported position even when no cash has moved.

Duration links the sensitivity of assets and liabilities

Duration is a way to describe how a valuation responds to changes in interest rates. Long-dated pension payments can be sensitive to those changes because discounting acts over many years. An LDI portfolio may hold bonds or use derivatives whose interest-rate exposure offsets part of the liability sensitivity. The objective is to reduce unwanted movement in the funding position, not necessarily to prevent the asset portfolio from ever falling in market value. If both assets and liabilities decline together, the scheme can be better matched than a portfolio whose assets remain stable while liabilities surge. Matching is imperfect when the yield curve changes shape, cash-flow dates differ or credit spreads affect the chosen assets differently. A single duration number compresses a complex exposure. Looking across maturities and scenarios is more informative than assuming that two portfolios with the same headline duration behave identically.

Interest-rate hedges do not cover every pension risk

The liability is not merely a long bond. Benefits may change with inflation subject to scheme-specific caps, floors or other rules, while longevity affects how long payments continue. Salary-related promises can introduce another source of uncertainty. Instruments that hedge a broad inflation index may not exactly reproduce the benefit formula, creating basis risk. A strategy can therefore hedge interest rates well and still leave meaningful inflation, longevity, credit, operational or sponsor risks. This matters when a high hedge ratio is presented as if it described complete protection. The ratio needs a defined exposure, measurement basis and set of exclusions. For example, a hypothetical scheme might neutralise much of its nominal rate sensitivity while remaining exposed to members living longer than assumed. That is not a contradiction; the two risks arise from different mechanisms. Reading the exclusions is as important as reading the reported percentage.

Bonds and derivatives create different cash requirements

An unleveraged bond portfolio requires funding the purchase of the bonds. Derivatives and repo-based structures can create substantial interest-rate exposure with less initial cash committed, leaving resources available for other assets. That flexibility comes with obligations: financing terms, margin arrangements, eligible collateral and the possibility of rapid demands for additional resources. Leverage is therefore not free capacity. It changes the relationship between market exposure and cash held in the strategy. A pension scheme can use a leveraged hedge for risk reduction relative to liabilities while the hedge vehicle itself remains exposed to liquidity stress. These statements describe different levels of the structure and can both be true. The analysis should distinguish the pension scheme, its investment fund, the counterparties and the contracts between them. Exposure measured across the entire scheme does not automatically reveal the cash that a particular vehicle must deliver today.

An improved funding position can coexist with a cash shortage

A simplified hypothetical scheme begins with assets of 100 and measured liabilities of 100. After a market shock, assume assets are worth 90 and liabilities 85. The measured surplus improves from zero to 5, even though assets have lost value. Now separately assume the hedge requires an immediate collateral transfer of 8 while only 3 of cash or eligible resources can be mobilised on time. The scheme faces a liquidity shortfall of 5 despite its improved funding position. These stipulated numbers illustrate a distinction, not a model linking a particular rate move to a margin call. Transferring collateral is also not automatically an economic expense: ownership and accounting treatment depend on the arrangement. The pressure arises from timing, eligibility and access. Long-term ability to finance benefits and immediate ability to meet contractual calls are related but different questions, and both must be monitored.

Liquidity means usable resources at the required deadline

A liquid-looking balance sheet is not enough if the relevant assets cannot become acceptable collateral by the deadline. Some assets can be sold quickly but settle later; others may face price discounts, fund redemption limits or legal restrictions. The scheme also needs cash for benefits, expenses and potentially commitments outside the LDI portfolio. A collateral plan therefore has to consider competing claims on the same resources. Counting an asset simultaneously as a buffer for several independent obligations overstates resilience. Stress analysis should consider the speed of moves, the period required to replenish resources and whether markets remain functional during that period. The question is not simply how much cash exists on a reporting date. It is how much usable liquidity can arrive at the correct legal entity, in the acceptable form, before each obligation falls due under adverse conditions.

Governance determines whether the buffer can actually be used

A written liquidity buffer is only useful if people and systems can activate it. Decisions may require trustees, investment managers, custodians and administrators to coordinate across different mandates and operating hours. Pooled investment vehicles can add another layer because many investors must provide resources through a common structure. Segregated arrangements have their own contractual and operational constraints. An effective process identifies who monitors thresholds, who can authorise transfers and what happens if the preferred source of cash becomes unavailable. It also distinguishes a routine replenishment from an emergency escalation. This is an institutional risk-management issue rather than a recommendation for a particular portfolio size or leverage level. The practical test is whether the documented sequence works under pressure, with incomplete information and simultaneous demands. A resource that exists economically but cannot be authorised or transferred in time is not an effective immediate buffer.

Forced selling can transmit stress beyond the pension scheme

The UK gilt-market disruption in 2022 illustrated how leveraged LDI structures could face large collateral demands after rapid yield increases. Official analysis describes sales of assets and feedback between falling prices, rising yields and further pressure on leveraged positions. The episode should not be reduced to the claim that all pension funds were insolvent or that hedging was inherently pointless. The important mechanism was the interaction of leverage, liquidity, operational timing and market capacity. When many institutions seek cash by selling similar assets at once, a strategy that appears manageable individually can amplify stress collectively. Even assets considered relatively safe in credit terms can suffer severe market-liquidity disruption. Historical episodes therefore inform scenario design, but they do not supply a universal forecast or a fixed rule for every jurisdiction. Scheme structure, collateral arrangements and market conditions remain essential to the interpretation.

Read funding, hedging and liquidity as three connected reports

A disciplined review separates three questions. Funding asks how measured assets compare with measured obligations on a stated basis. Hedging asks which changes in those obligations are offset, by what instruments and with what residual risks. Liquidity asks how benefits, expenses and contractual calls will be met across plausible timelines. None of the three can substitute for the others. Useful reporting explains assumptions, sensitivity by maturity, collateral eligibility, replenishment processes and the dependence on sponsor or external resources. It also makes clear when figures refer to the entire pension scheme and when they refer only to an investment vehicle. The objective is not to infer safety from one funding ratio or danger from one asset-price decline. It is to understand whether the system can maintain its intended exposures and pay its obligations when markets move quickly. This is an explanatory framework, not personalised pension or investment advice.

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