Executive summary
- Gross leverage overstates risk for hedged books and understates it for concentrated ones; economic leverage adjusted for risk is the meaningful measure.
- Margin requirements are procyclical: they rise precisely when the ability to meet them falls.
- The binding constraint in a crisis is funding runway in days, not solvency on paper.
- Redemption terms, gate provisions and financing tenor should be modelled together as a single liability profile.
- Concentration among a small number of prime brokers is itself a first-order risk.
Three measures of leverage and what each hides
Gross leverage sums long and short notional and divides by capital. It is simple and it is misleading: a matched pairs book with gross leverage of eight may carry less risk than an unhedged long book at two. Net leverage nets longs against shorts, which flatters portfolios where the two legs are not genuinely offsetting.
L_risk = ( σ_portfolio × NAV_exposure ) / ( σ_target × NAV )
- σ_portfolio
- — estimated volatility of the levered book
- σ_target
- — volatility the fund is mandated to run
- NAV
- — net asset value
- L_risk
- — risk-based leverage, the ratio of run risk to mandated risk
Risk-based leverage is the most informative of the three because it is denominated in the same unit as the loss tolerance. Its weakness is that it depends on a volatility estimate, and volatility estimates are lowest immediately before the periods in which they matter.
The margin spiral
The mechanism is well documented and repeats with little variation. Prices fall; mark-to-market losses reduce equity; volatility rises, so the broker's margin model demands more collateral against the same position; the fund sells to raise collateral; the sales push prices lower; the cycle repeats. Nothing in the sequence requires anyone to be wrong about fundamentals.
- An initial price shock reduces fund equity and increases measured volatility.
- Initial and variation margin requirements increase, often with a haircut widening on the same collateral.
- The fund liquidates its most liquid assets first, worsening the residual liquidity profile of the book.
- Remaining positions become harder to value and to finance, and further haircuts follow.
- Redemption requests arrive, adding a second, unrelated claim on the same cash.
Funding runway and the liability profile
The practical measure of resilience is the number of days the fund can meet margin calls and redemptions from available cash and unencumbered assets, under a stress in which financing tenor is not rolled. This requires modelling three liability streams together: margin variation, financing maturity and investor redemption rights net of gates and lock-ups.
| Day | Margin call | Redemption claim | Available liquidity | Runway status |
|---|---|---|---|---|
| 1 | 18m | 0 | 120m | Comfortable |
| 5 | 46m | 0 | 62m | Monitoring |
| 10 | 71m | 40m | 9m | Action required |
| 15 | 88m | 40m | Negative | Forced sale |
Counterparty concentration and financing terms
Financing terms are risk parameters, not procurement details. Tenor, minimum-notice periods for term changes, cross-default clauses, rehypothecation rights and the definition of a material adverse change determine whether the fund controls its own liquidation. A fund financed overnight by two counterparties has a different risk profile from an identical portfolio financed on committed 90-day terms across five.
- Track the share of financing and of margin exposure by counterparty and by tenor bucket.
- Model the withdrawal of the largest financing counterparty as a standing scenario.
- Negotiate notice periods for margin-model changes wherever possible.
- Hold unencumbered high-quality assets sized against the modelled peak call, not the average.
Practical example
A relative-value fund runs 400 million of capital at gross leverage of six, holding a sovereign basis position financed in repo. A 40 basis point adverse move in the basis produces a mark-to-market loss of roughly 9 percent of capital. The move raises realised volatility, and the broker's margin model increases initial margin by 35 percent, requiring 52 million of additional collateral.
The fund holds 60 million of unencumbered cash, so the call is met — but the runway falls to eight days at the observed rate of margin escalation. The correct action at that point is to cut the position while it remains saleable, accepting the realised loss, rather than to defend the trade with the remaining buffer. Funds that survive this sequence are typically those that pre-agreed the trigger before the stress began.
Limitations and caveats
- Margin models are proprietary to counterparties, so projections are approximations with meaningful error.
- Liquidity assumptions calibrated on normal markets systematically overstate realisable value in stress.
- Redemption behaviour is behavioural and correlates with performance in ways that are difficult to model.
- Committed financing carries a cost that must be justified against a risk that may not materialise for years.
Conclusion
Leverage does not change the expected value of a position; it changes the set of paths on which the position survives. Risk management for a levered fund is therefore path management, and the key variable is days of funding, not percentage of loss.
The disciplined approach is to size positions against the projected peak collateral call under stress, and to pre-commit to de-risking triggers that do not require a judgement call in the middle of a spiral.
References
- Market Liquidity and Funding Liquidity — Review of Financial Studies, 2009
- Margining Practices and Procyclicality Review — Bank for International Settlements
- Non-Bank Financial Intermediation Monitoring Report — Financial Stability Board
Author bio
Jonas Mohamed Osman Abdelghafour, known as Yonas Osman is an actuary, FRM and financial risk professional specialising in banking, insurance, model risk, capital modelling and quantitative risk management.