Stress Testing

IntermediateRisk Management2 min read

Quick Definition

A simulation technique used to evaluate how a portfolio or financial institution would perform under extreme adverse conditions.

What Is Stress Testing?

Stress testing evaluates the resilience of a portfolio or institution by modeling its performance under severe but plausible adverse scenarios. It answers: "What happens if things go really wrong?"

Types of Stress Tests:

TypeApproachExample
HistoricalReplay past crises"How would my portfolio do in 2008?"
HypotheticalModel theoretical scenarios"What if rates rise 500 basis points?"
ReverseFind what would cause failure"What scenario would cause a 50% loss?"
SensitivityTest single variable changes"Impact of 10% drop in stock market"

Portfolio Stress Test Example:

ScenarioStocksBondsPortfolio (60/40)
2008-style crash-50%+5%-28%
1970s stagflation-15%-10%-13%
2022 rate shock-25%-13%-20.2%
COVID crash-34%+3%-19.2%

How to Stress Test Your Portfolio:

  1. List all holdings with current allocation
  2. Apply historical scenario returns to each asset
  3. Calculate portfolio-level impact
  4. Assess if the loss is acceptable for your situation
  5. Adjust allocation if projected losses exceed your risk tolerance

Institutional vs. Individual:

  • Banks must pass Fed stress tests (CCAR) annually
  • Individual investors should stress test at least annually or before major life events
  • Free tools: Portfolio Visualizer, Vanguard's risk tolerance tools

Stress Testing Example

  • 1Running a 2008-scenario stress test on a 60/40 portfolio shows a potential -28% drawdown
  • 2Banks must pass annual Fed stress tests to prove they can survive severe economic downturns