Table of Contents

Core Framework: Liability Characteristics Driving Asset Choice

For strategic asset allocation at an insurer, I was thinking the key aspects of liabilities that drive asset choices are:

  • Duration
  • Convexity
  • Optionality
  • Predictability of cashflows

That’s a solid framework. Those four liability characteristics map well to asset selection. Let me build on your thinking and stress-test it a bit.

Duration

Duration is the most fundamental — it drives the core interest rate hedge. For a life insurer with long-dated liabilities, this pushes toward long corporate bonds, gilts, and infrastructure debt. The goal is to immunise the PV of liabilities against parallel rate shifts.

Convexity

Convexity matters because duration is only a first-order approximation. Liability convexity (especially for savings/annuity books) is often higher than you’d get from a simple bond portfolio, which creates a mismatch that worsens in volatile rate environments. This is why insurers reach for mortgage-backed securities, callable bonds (negatively convex, so used carefully), or swaptions to fine-tune the convexity profile.

Optionality

Optionality in liabilities is arguably the trickiest dimension — things like surrender options, with-profits guarantees, variable annuity riders, or policy loans. These create embedded short option positions on rates, equity, or both. The natural asset response is to hold offsetting long optionality — swaptions, interest rate caps/floors, equity options — though this is expensive and introduces basis risk. It also pushes toward more conservative asset allocation to reduce the likelihood of options going deep in the money.

Predictability of Cash Flows

Predictability of cash flows essentially drives the liquidity and credit quality decisions. Highly predictable liabilities (like immediate annuities) support illiquid, buy-and-hold assets — private credit, infrastructure equity, real estate — because you can harvest the illiquidity premium with confidence. Less predictable books (P&C short-tail, unit-linked) require more liquid, mark-to-market portfolios.

Additional Dimensions

A few additional dimensions worth considering:

Currency — if liabilities are sterling-denominated, FX risk in assets needs hedging or avoidance
Inflation linkage — longevity-exposed books have real liability growth, pushing toward index-linked gilts or inflation-linked infrastructure
Regulatory capital sensitivity (Solvency II / IFRS 17 lens) — asset choices affect SCR and the matching adjustment eligibility, which can be as binding a constraint as the liability profile itself
Correlation with mortality/longevity risk — for life books, equities can be a partial natural hedge if you believe equity performance correlates with economic conditions that also affect longevity

Your four factors are the right starting point — they capture the core ALM problem. The capital and regulatory layer then acts as a filter on which asset solutions are actually viable in practice.

What’s the specific book of business you’re thinking about?

Why Is Holding Options Expensive?

why is holding options expensive

Good question — there are a few distinct reasons, and they compound each other.

Implied Volatility Premium

The most fundamental reason. Options are priced using implied volatility, which systematically exceeds realised volatility over time. Sellers of options earn a risk premium for bearing tail risk — so buyers structurally overpay relative to the “fair” cost based on actual subsequent moves. This vol risk premium is persistent and well-documented across rates, equity, and FX markets.

Theta Decay

Options lose time value continuously as expiry approaches. If the underlying doesn’t move enough, the option expires worthless or below premium paid. For an insurer running a long options hedge, you’re constantly bleeding theta — and because liability optionality is often long-dated or perpetual, you’re rolling hedges repeatedly, crystallising that decay over and over.

Bid-Offer Spreads

Options markets — particularly for long-dated swaptions or bespoke structures — are far less liquid than the underlying cash markets. Bid-offer spreads can be wide, especially at the tenors and strikes an insurer actually needs (deep out-of-the-money, 10-30 year expiries). Every roll incurs that transaction cost again.

Basis Risk Between Liability Optionality and Hedging Instruments

The options you can buy in the market rarely match the embedded options in liabilities precisely. A with-profits guarantee or a surrender option has its own exercise logic, policyholder behaviour dependencies, and payoff profile. The closest tradeable instrument is an approximation — so you either over-hedge (paying for more than you need) or accept residual basis risk. Either way there’s a cost.

Collateral and Funding Costs

Bought options require upfront premium payment, tying up capital. If you’re using OTC derivatives, variation margin calls create liquidity demands. Under Solvency II, the SCR treatment of derivatives can also be unfavourable, adding a regulatory capital cost on top of the economic cost.

The Practical Implication

This is why most insurers don’t try to fully hedge liability optionality through bought options. Instead they tend to:

Accept residual optionality risk and hold capital against it
Reduce liability optionality at source through product design (e.g. surrender charges, market value adjusters)
Use natural hedges where possible (e.g. a portfolio with some negative convexity assets partially offsets positive convexity liability optionality)
Reserve options hedging for the most material, capital-intensive tail exposures only

The cost of hedging is essentially the price of the guarantee you sold to policyholders — and if you hedge it fully, you’re left earning very little spread, which raises the question of whether the product is economically viable in the first place.

Can Dynamic Management Actions Replace Options?

can dynamic management actions replace options

Great question — this is a live debate in ALM and reserving circles. The short answer is partially, but with important limitations.

The Theoretical Case for Dynamic Hedging

Delta hedging replicates an option payoff by continuously adjusting the underlying position as the market moves. In the Black-Scholes world, a delta-hedging strategy perfectly replicates a bought option at a cost equal to realised volatility — so if realised vol is below implied vol, dynamic hedging is cheaper than buying the option outright. This is the core argument for using management actions rather than bought options.

For an insurer this might look like:

Reducing equity exposure as markets fall (to replicate a put)
Extending or shortening duration dynamically as rates move
Adjusting asset allocation in response to liability value changes

Why It Breaks Down in Practice

Discrete Rebalancing vs Continuous Hedging

Real portfolios rebalance periodically, not continuously. Gamma — the rate of change of delta — means that in fast-moving markets, the hedge lags the liability movement. The larger the moves and the less frequently you rebalance, the greater the replication error. This is precisely when you most need the hedge to work.

Transaction Costs Erode the Saving

Every rebalance incurs bid-offer, market impact, and potentially tax costs. A strategy that looks cheap in theory can become expensive once you account for the friction of frequent trading — particularly in stressed markets when spreads widen.

Liquidity and Market Impact

In a stress scenario — exactly when liability optionality bites hardest — the assets you need to sell may be illiquid. A large insurer delta-hedging a big equity guarantee by selling equities into a falling market faces significant market impact, and may itself contribute to the dislocation. The hedge works best when you need it least.

Regulatory and Reserving Treatment

Under Solvency II, management actions are only credible in the ORSA and internal model if they are:

Documented and board-approved in advance
Demonstrably executable under stress
Consistent with policyholder reasonable expectations

Regulators are sceptical of dynamic strategies that assume perfect execution. The PRA in particular has pushed back on internal models that give full credit to management actions without robust evidence they’d work in practice. So the capital relief may be less than expected.

Basis and Model Risk

Dynamic hedging relies on a model to calculate delta. If the model is wrong — wrong volatility surface, wrong correlation assumptions, wrong policyholder behaviour — the hedge ratio is wrong, and errors compound over time. Bought options transfer this model risk to the counterparty; dynamic hedging keeps it on your book.

Gap Risk

Markets can jump discontinuously — overnight rate moves, equity circuit breakers, flash crashes. A delta hedge has no protection against gaps because there’s no opportunity to rebalance between the pre- and post-gap price. A bought option pays off regardless of how the market got there.

Where Dynamic Management Actions Do Add Value 

Slow-moving risks where rebalancing frequency is adequate — duration management in normal rate environments for instance
Supplementing rather than replacing options — using dynamic hedging for the "expected" scenario while bought options cover the tail
Internal capital management — even if not fully credible to regulators, dynamic strategies reduce expected loss and smooth P&L
Where the gamma is low — away from the strike and away from expiry, delta hedging works reasonably well; it's near-the-money and near-expiry where gamma is high and replication error is greatest

The Honest Conclusion

Dynamic management actions are a complement to options, not a substitute. They work well in benign, liquid, continuously-moving markets — which is exactly not the environment in which liability optionality typically crystallises. The residual risk you’re left with after dynamic hedging — gap risk, liquidity risk, model risk, execution risk — is correlated with the scenarios where the liability optionality is most costly. That correlation is the fundamental problem, and it’s why bought options, despite their cost, retain a role in a well-structured hedging programme.

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