美联储-黑天鹅与金融稳定_建立韧性的框架（英）-2025_43页_583kb

Black Swans and Financial Stability: A Framework for Building Resilience

Summary

The paper defines a "black swan" as an unknown unknown event with high impact—fundamentally unknowable and catastrophic. It differentiates black swans from grey swans (known unknowns) and white swans (known knowns). Black swans stem from the inherent uncertainty in complex adaptive systems (CAS), such as the modern financial system, making them impossible to predict or prevent. The paper argues that mitigation must focus on building financial system resilience rather than fighting the last crisis.

Key Achievements

1. Clarity on Black Swans: A precise taxonomy refines Nassim Taleb’s concept by defining black swans as events with no prior conception of possibility, contrasting with grey and white swans.
2. Complex Adaptive Systems (CAS): The 2008 crisis and COVID-19 pandemic are labeled as black swans due to their systemic unpredictability in interconnected financial networks.

A Resilience Principle

The paper introduces three pillars for resilience-focused policies:

• Adaptable: Policies must adjust dynamically to evolving risks (e.g., circuit breakers).
• Universal: Broad coverage to prevent regulatory arbitrage (e.g., universal liquidity buffers).
• Systemic: Addressing the entire financial system’s vulnerability to avoid cascading failures (e.g., backstops like lender-of-last-resort facilities).

Policy Examples

1. Automatic Stabilizers: Rule-based responses to early-warning indicators (e.g., capital ratios or trading volumes).
2. Buffers: Mandatory reserves (e.g., CCyB or universal liquidity buffers) to absorb shocks during stress.
3. Backstops: Official guarantees or operational support as a final line of defense (e.g., emergency lending or operational continuity measures).

Conclusion

Black swans cannot be prevented but resilience can minimize their damage. The paper argues for bold official-sector policies—despite market limitations—to create a financial system capable of absorbing catastrophic tail risks.