Why Stress Testing?
VaR assesses risk under "normal market conditions," but it is extreme events that truly destroy portfolios:
- 2008 Financial Crisis: Global stocks down 50%+
- 2020 Pandemic Crash: 30%+ decline in 1 month
- 2022 Rate Hikes: Tech stocks down 40%+
The purpose of stress testing is to ask: "If these scenarios happen again, can my portfolio withstand it?" Use Regime and Risk analysis to understand which risk regime the market is currently in.
Designing Stress Test Scenarios
Scenario 1: Market Crash
| Scenario | Market Decline | Expected Portfolio Decline |
|---|---|---|
| Mild Crash | -20% | ? |
| Moderate Crash | -30% | ? |
| Severe Crash | -40% | ? |
Test method:
- Calculate each holding's actual decline in 2008, 2020
- Assume the same decline repeats, calculate total portfolio loss
- Assess whether you can withstand it
Scenario 2: Rate Spike
Suitable for evaluating bonds and growth stocks:
- Rate increase 1% -> Bond prices fall approximately 5-10%
- Rate increase 2% -> High-valuation growth stocks may fall 30-50%
Scenario 3: Industry-Specific Risk
- Tech crash 50% (like 2000 dot-com bubble)
- Financial crash 60% (like 2008)
- Energy crash 70% (like 2014 oil price crash)
If your portfolio is concentrated in one industry, this test is important.
Scenario 4: Liquidity Crisis
Assume all your holdings are suspended for 1 month, unable to sell:
- Do you have enough cash for emergencies?
- Will you be forced to liquidate?
Interpreting Test Results
Result 1: Can Withstand
If worst-case loss < 20% and you have sufficient cash flow:
- Continue current strategy
- Retest quarterly
Result 2: Barely Withstand
If loss is 20-40%:
- Consider reducing position size
- Increase cash allocation
- Use hedging strategy
Result 3: Cannot Withstand
If loss > 40%:
- Must adjust portfolio
- Reduce high-risk asset allocation
- Increase defensive assets like bonds and cash
- Reassess whether investment goals are realistic
Adjusting Strategy Based on Test Results
Adjustment 1: Asset Allocation
| Test Result | Suggested Adjustment |
|---|---|
| Barely Withstand | Stocks 60% -> 50%, Bonds 20% -> 30% |
| Cannot Withstand | Stocks 60% -> 40%, Increase cash to 30% |
Adjustment 2: Industry Diversification
If tests show over-sensitivity to one industry:
- Reduce holdings in that industry
- Increase defensive industries (e.g., utilities, healthcare)
Adjustment 3: Hedge Protection
Use options, inverse ETFs to hedge downside risk. See Hedging Strategy Guide.
Adjustment 4: Cash Reserve
After stress testing, you may find you need more cash buffer:
- Emergency fund: 6-12 months living expenses
- Investment cash: 10-20% for buying opportunities
Summary
Core value of stress testing:
- Pre-assessment -- know extreme risks before losses occur
- Mental preparation -- know the worst case, stay calm when it actually happens
- Strategy adjustment -- optimize asset allocation based on test results
Remember: stress testing is not meant to scare you, but to prepare you. The real risk is not the market falling, but not being prepared for it. Use Market Pulse to track market conditions in real time and prepare early.
Use with VaR Value at Risk for a comprehensive risk assessment in both normal and extreme scenarios.