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gateway/knowledge/trading/strategies/structured-assets/carry-senior-mezzanine.md

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+---
+description: "CDO carry strategy that sells a senior or mezzanine tranche and delta-hedges by buying the CDS index, earning the index spread premium over the tranche cost."
+tags: [structured-assets, cdo, carry, senior-tranche, mezzanine, delta-hedge, cds-index]
+---
+
+# Carry — Senior/Mezzanine Tranche with Index Hedging
+
+**Section**: 11.3 | **Asset Class**: Structured Assets | **Type**: Carry / Delta-Hedged
+
+## Overview
+This is the mirror image of the equity tranche carry trade (Section 11.2). Instead of buying a low-quality tranche and hedging with a short index position, the trader sells a high-quality (senior or mezzanine) tranche and delta-hedges by buying the CDS index. The premiums received from the index exceed the premiums paid on the short senior/mezzanine tranche, generating positive net carry.
+
+## Construction / Mechanics
+**Position:**
+- Short the senior/mezzanine tranche (protection buyer): pay spread S_senior
+- Long the CDS index (protection seller): receive spread S_index
+
+**Delta (hedge ratio):** Same formula as Eq. (487):
+
+```
+Δ_ix = D / D_ix                                              (487)
+```
+
+where D is the risky duration of the senior/mezzanine tranche and D_ix is the risky duration of the CDS index.
+
+**Economics:**
+- Premium received from the long index position > premium paid on the short senior/mezzanine tranche
+- This trade is the opposite of the equity tranche strategy: the index premiums fund the tranche premium cost
+
+## Return Profile
+Earns positive carry as long as defaults do not trigger payouts on the index position that exceed the spread income. The hedged position is approximately spread-neutral to small parallel credit spread moves. The long index position compensates for portfolio-level default losses; the short senior tranche position profits from non-extreme loss scenarios.
+
+## Key Parameters / Signals
+| Parameter | Description |
+|-----------|-------------|
+| Δ_ix = D / D_ix | Hedge ratio: senior/mezzanine tranche risky duration / index risky duration |
+| S_index | Spread received on long CDS index position |
+| S_senior | Spread paid on short senior/mezzanine tranche |
+| Net carry | Δ_ix × S_index - S_senior (approximately) |
+
+## Variations
+- Adjust the quality of the tranche sold (from mezzanine to super-senior) to tune the risk/carry trade-off.
+- Use multiple tranches at different quality levels to diversify the credit curve exposure.
+
+## Notes
+- This strategy is "opposite" to the equity tranche carry trade: the long CDS index position exposes the trader to portfolio-level defaults, while the short senior tranche benefits from low-to-moderate loss scenarios.
+- The net carry is typically lower than the equity tranche trade because senior tranche spreads are lower.
+- Correlation risk applies here as well: if correlation decreases (idiosyncratic defaults increase), the index position is hit harder than a diversified senior tranche.
+- The CDS index is a liquid instrument; basis risk between the index and individual tranche spreads is a key residual risk.