How do long-short equity strategies work and what are the key performance metrics?

Question

AcadiFi · Accepted Answer

Long-short equity is a hedge fund strategy that takes both long positions (betting on appreciation) and short positions (betting on decline). It aims to generate alpha from stock selection while controlling market exposure.

**Basic Mechanics**

Starting with $100M capital:
- Go long $120M of undervalued stocks (1.2x leverage)
- Short $80M of overvalued stocks
- **Net exposure:** $120M - $80M = $40M (40% net long — directional bias)
- **Gross exposure:** $120M + $80M = $200M (total capital at risk)

**Return Decomposition**

The portfolio return has three sources:
1. **Alpha (long):** Return from selecting good longs minus the benchmark
2. **Alpha (short):** Return from selecting good shorts (profits when they decline)
3. **Beta exposure:** Net market exposure × market return
4. **Rebate income:** Interest earned on short sale proceeds (short rebate)

```mermaid
graph LR
    A[Long-Short Return] --> B[Long Alpha]
    A --> C[Short Alpha]
    A --> D[Market Beta × Net Exposure]
    A --> E[Short Rebate Income]
    A --> F[- Borrowing Costs - Fees]
```

**Key Performance Metrics**

| Metric | Formula | What It Measures |
|---|---|---|
| Net exposure | (Long - Short) / Capital | Directional market bet |
| Gross exposure | (Long + Short) / Capital | Total leverage |
| Long/Short ratio | Long / Short | Balance of positioning |
| Alpha | Return - (Beta × Market Return) | Skill-based return |
| Information Ratio | Alpha / Tracking Error | Risk-adjusted alpha |
| Sortino Ratio | (Return - MAR) / Downside Dev | Downside risk-adjusted return |

**Example:** Meridian Long-Short Fund returns 11% in a year where the market returns 8%:
- Net exposure: 40%, so beta contribution = 40% × 8% = 3.2%
- Alpha = 11% - 3.2% = 7.8% (from stock selection on both sides)
- Short rebate contributed ~0.5%
- Net alpha from stock picking = 7.3%

**Short Selling Risks**

- **Unlimited loss potential:** A short position can lose more than 100% (stock can theoretically go to infinity)
- **Short squeeze:** Heavy short interest can trigger forced covering, driving prices higher
- **Borrow cost:** Hard-to-borrow securities command premium lending fees (1-10%+ annually)
- **Recall risk:** The lender can recall shares, forcing position closure at inopportune times

**Market Neutral vs. Directional Long-Short**

- **Market neutral:** Net exposure = 0% (equal long and short). Pure alpha strategy.
- **Directional long-short:** Net exposure = 20-60% long. Alpha + controlled beta exposure.

For the CFA Level III exam, understand how to calculate net and gross exposure, decompose returns into alpha and beta components, and evaluate whether a long-short strategy suits a client's objectives. Practice with our CFA III alternatives materials.

How do long-short equity strategies work and what are the key performance metrics?

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Related Questions

Practice Questions

Metric	Formula	What It Measures
Net exposure	(Long - Short) / Capital	Directional market bet
Gross exposure	(Long + Short) / Capital	Total leverage
Long/Short ratio	Long / Short	Balance of positioning
Alpha	Return - (Beta × Market Return)	Skill-based return
Information Ratio	Alpha / Tracking Error	Risk-adjusted alpha
Sortino Ratio	(Return - MAR) / Downside Dev	Downside risk-adjusted return