Systemic risk is the risk that disruption to the financial system, or an important part of it, impairs financial services enough to cause serious harm to the real economy. Payments that cannot settle, credit that becomes unavailable and broken channels for transferring risk can affect firms and households far beyond the original loss-making institution. The concern is the system's ability to keep functioning, rather than the size of one investor's loss.
This service-and-economy perspective follows the Reserve Bank of Australia's systemic-risk discussion. A whole financial system need not collapse: a sufficiently important market, institution or infrastructure can be disrupted while other parts continue operating.
Follow the loss, then ask what stops working
Consider two fictional banks. Bank A suffers an external loss that prevents full repayment of its obligations. Bank B holds a claim on A recorded at USD 8 million and starts with USD 10 million of equity. Assume the claim's recovery value is 50% of that recorded amount. Ignore collateral, netting, taxes and any change in B's other assets or liabilities.
| Bank B's position | USD millions |
|---|---|
| Claim on A before the disruption | 8 |
| Claim's recovery value | 4 |
| Direct loss on the claim | 4 |
| Equity before the loss | 10 |
| Equity after the loss | 6 |
The loss travels through a contractual exposure: A's inability to repay reduces the value of B's asset, and the reduction is absorbed by B's equity. This is a direct counterparty credit risk channel.
Original synthetic example, in USD millions. Solid arrows follow the stipulated loss transmission; dashed arrows identify conditional wider channels. The ledger holds B's other balance-sheet values fixed and does not establish system-wide disruption.
The calculation does not prove a systemic event. B still has positive equity in this simplified balance sheet. That does not establish that B can meet its next payment deadline, either: available cash and funding liquidity risk require a separate assessment. Nor have we shown that B stops lending, that payments fail or that other institutions are unable to replace its services.
To make the systemic case, follow the consequences. Does B withdraw funding from other institutions? Does it sell assets into a thin market? Do customers lose access to a critical service? Can substitutes take over quickly enough? There is no universal amount of transmitted loss that answers those questions.
A network can amplify a shock without a chain of defaults
Several mechanisms can threaten the provision of financial services:
- Contractual connections. Unpaid claims or delayed payments weaken counterparties and can create further cash demands. Contagion describes transmission or amplification; it is a mechanism through which systemic risk may arise, rather than a synonym for systemic consequences.
- Common exposures and responses. Institutions holding similar assets can be hit together by the same shock. If they all try to sell, fire sales can push prices down, weaken other holders and prompt further selling. Selling can protect one firm's position while worsening conditions for the group. The membership lesson Why Manage Financial Risk? develops these endogenous effects in its section on fire-sale externalities; a public preview is available.
- Shared infrastructure. A critical payment or technology service can fail without first causing a bank insolvency. The Bank of England's operational-resilience analysis examines how common dependencies and interconnections can interrupt vital services.
These channels can interact. A payment outage can create a cash shortfall; an attempt to obtain cash can worsen market liquidity; weaker prices can undermine confidence and funding. Assessing each institution in isolation misses the effects of its response on everyone else.
Systemic and systematic answer different questions
Systematic risk is exposure to common market factors that broad diversification does not eliminate. A market-wide repricing can produce systematic losses while trading, payments and credit provision continue functioning. It becomes a systemic concern when the shock and the system's vulnerabilities threaten those functions with serious consequences for the economy.
Conversely, an operational failure at a critical service provider can pose systemic risk without beginning as a common-factor return shock. Similar spelling does not make the concepts interchangeable.
For a quant, a useful stress test therefore connects exposures to behaviour, funding needs and service continuity. A portfolio loss estimate alone does not supply that connection. The analysis also needs assumptions about recovery, asset-sale capacity, payment timing, counterparties' responses and the availability of substitutes.
Systemic importance should not be read as a promise of rescue. The FSB's resolution standard aims to preserve vital economic functions while allowing orderly resolution without taxpayer losses from solvency support. That is a policy objective; the applicable powers and outcome depend on the jurisdiction and circumstances.
Sources
- Alexander J. McNeil, Rüdiger Frey and Paul Embrechts, Quantitative Risk Management: Concepts, Techniques and Tools, revised edition, Princeton University Press, 2015, §1.4.1, pp. 30–32: the societal view, spillovers, systemic importance and the danger of correlated risk-management responses; §6.4.2, p. 209, distinguishes common-factor systematic risk from diversifiable idiosyncratic risk.
- Reserve Bank of Australia: Sources and Management of Systemic Risk, Financial System Inquiry submission, March 2014, §4.1: systemic disruption, real-economy effects and sources of amplification. Used for the conceptual framework, rather than its historical Australian statistics.
- Bank of England: Operational resilience in a macroprudential framework, Financial Stability Paper 50, August 2024, §§1 and 4: vital services, shared dependencies and operational transmission channels.
- Financial Stability Board: Key Attributes of Effective Resolution Regimes, revised version 2024: orderly resolution and continuity of vital economic functions. The bank ledger and diagram here are original illustrations.