Unsystematic Risk
Quick Definition
Company-specific or industry-specific risk that can be reduced or eliminated through diversification.
What Is Unsystematic Risk?
Unsystematic risk (also called specific risk, diversifiable risk, or idiosyncratic risk) is the risk unique to a particular company or industry. Unlike systematic risk, it can be virtually eliminated through proper diversification.
Sources of Unsystematic Risk:
| Source | Example |
|---|---|
| Management Risk | CEO scandal, poor leadership decisions |
| Financial Risk | Company takes on too much debt |
| Business Risk | Product failure, loss of key customer |
| Regulatory Risk | New regulations targeting specific industry |
| Legal Risk | Lawsuit, patent infringement |
| Competitive Risk | New competitor disrupts market |
Diversification Effect:
| Number of Stocks | Unsystematic Risk Remaining |
|---|---|
| 1 stock | 100% |
| 5 stocks | ~55% |
| 10 stocks | ~35% |
| 20 stocks | ~20% |
| 30 stocks | ~10% |
| 50+ stocks | ~5% |
| Market index | ~0% (only systematic risk) |
Key Insight: Because unsystematic risk can be diversified away, the market does not compensate investors for bearing it. Only systematic risk earns a risk premium.
Real Examples:
- Enron (2001): Investors concentrated in Enron stock lost everything — a diversified portfolio barely noticed
- Boeing 737 MAX (2019): Company-specific crisis caused 25% stock drop, but the aerospace index was resilient
- Silicon Valley Bank (2023): Bank-specific risk wiped out shareholders, but broad financial ETFs recovered quickly
Unsystematic Risk Example
- 1Enron's collapse was unsystematic risk — only Enron investors suffered, not the broad market
- 2Holding 30+ stocks across sectors eliminates most unsystematic risk from your portfolio
Related Terms
Systematic Risk
Market-wide risk that affects all securities and cannot be eliminated through diversification, also called market risk.
Diversification
Spreading investments across various assets, sectors, and geographies to reduce risk without sacrificing expected returns.
Concentration Risk
The risk of amplified losses when a portfolio is heavily weighted in a single asset, sector, or investment type.
Diversifiable Risk
Risk specific to individual securities or sectors that can be eliminated by holding a well-diversified portfolio of investments.
Standard Deviation
A statistical measure of how spread out returns are from the average, quantifying investment volatility and risk.
Risk Management
The systematic process of identifying, assessing, and mitigating financial risks to protect portfolio value and achieve investment objectives.
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