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Use VaR (Value-at-Risk) carefully with long-tail events

Use VaR (Value-at-Risk) carefully with long-tail events

07/13/2025
Matheus Moraes
Use VaR (Value-at-Risk) carefully with long-tail events

In an era of unprecedented financial complexity, understanding risk is essential. Value-at-Risk (VaR) offers a simple snapshot, but its blind spots can prove catastrophic when rare events strike. This article explores how to harness VaR wisely and prepare for the unimaginable.

Understanding Value-at-Risk: Strengths and Limitations

Value-at-Risk has earned popularity for its ability to distill a portfolio’s risk into a single, intuitive number. By estimating the maximum loss at a specified confidence level—often 95% or 99%—it allows institutions to compare risk profiles across diverse assets. Yet, its elegance masks a critical flaw.

VaR only describes the threshold loss, not the severity of outcomes beyond that line. If a 1-day 99% VaR is $10 million, it tells nothing about whether the worst 1% of losses cluster around $11 million or skyrocket to $100 million. This gap leaves decision-makers exposed when extreme market turmoil unfolds.

The Peril of Fat Tails: When the Unthinkable Strikes

Financial returns rarely follow a perfect bell curve. Instead, they exhibit rare but severe losses that occur more frequently than standard models suggest. Known as fat-tail or tail risk, these events can overwhelm a VaR-driven strategy.

History offers stark reminders: a one-day equity market plunge of 10% or more during the 2008 crisis, and the unexpected shock of COVID-19 in 2020. In both cases, losses stretched multiple times beyond typical VaR estimates. Over-reliance on historical data that omits these crises can lull risk managers into a false sense of security.

  • 2008 Financial Crisis: Daily swings exceeding ten standard deviations.
  • COVID-19 Market Shock: Rapid, unprecedented volatility spikes.
  • Black Swan Events: Phenomena deemed nearly impossible by normal models.

Beyond VaR: Alternative Tools for Extreme Risk

Recognizing VaR’s blind spots, regulators and practitioners have embraced supplementary measures. Conditional VaR (CVaR), known as Expected Shortfall, calculates the average loss in the worst-case tail, offering insight into the depth of potential ruin. Meanwhile, Extreme Value Theory (EVT) applies specialized distributions to model the magnitude of rare losses.

Stress testing takes these concepts further. By simulating scenarios at multiples of VaR—three, five, even ten times the standard estimate—organizations uncover vulnerabilities and design contingency plans for worst-case trajectories.

Practical Steps for Robust Risk Management

Integrating these tools demands a structured approach. First, ensure your data series include periods of crisis and are refreshed regularly to reflect current dynamics. Short lookbacks may miss critical events; overly long ones can dilute recent risk patterns.

Next, adopt a comprehensive risk management framework that layers methods:

  • Calculate VaR at multiple confidence levels and horizons.
  • Estimate CVaR to gauge average tail severity.
  • Apply EVT to refine probability estimates for extreme moves.
  • Conduct stress tests at several multiples of VaR to test resilience.

Finally, build contingency plans. Determine capital buffers or insurance structures that activate when losses breach stress thresholds. Communicate these plans across your organization to ensure swift, coordinated responses.

Regulatory Trends and Organizational Preparedness

Regulators have recognized VaR’s shortcomings. The Basel Committee on Banking Supervision now emphasizes Expected Shortfall for market risk. Firms that cling solely to VaR risk non-compliance and insufficient capital in crises.

Beyond regulations, a culture of vigilance and learning is vital. Encourage open discussions about hypothetical worst-case events, even those deemed remote. By fostering a proactive risk mindset, institutions can adapt quickly when markets defy all expectations.

Conclusion: Embrace Uncertainty, Plan for Survival

Value-at-Risk remains a useful tool, but it’s only one piece of the puzzle. To navigate the unpredictable seas of modern finance, supplement VaR with CVaR, EVT, and rigorous stress testing. Prepare strategies for scenarios that exceed ten times your typical loss estimates. Recognize that extreme events, while rare, can reshape markets overnight.

Ultimately, risk management is not about predicting the next crisis perfectly—it’s about ensuring that when the unthinkable arrives, you have the foresight, tools, and resilience to endure. By using VaR carefully and planning for long-tail events, you can transform uncertainty into a competitive advantage.

Matheus Moraes

About the Author: Matheus Moraes

Matheus Moraes