How do you decompose a swap spread into its credit, liquidity, and supply-demand components?

Swap spreads reflect the difference between the fixed rate on an interest rate swap and the Treasury yield at the same maturity. While often interpreted as a pure credit risk measure, swap spreads actually embed multiple components that can push them in unexpected directions, including negative.\n\nDecomposition:\n\nSwap Spread = Credit Component + Liquidity Component + Supply/Demand Component + Regulatory Component\n\nComponent Breakdown:\n\n`mermaid\ngraph TD\n A[\"Swap Spread
(Swap Rate - Treasury Yield)\"] --> B[\"Credit Component
LIBOR/SOFR counterparty risk\"]\n A --> C[\"Liquidity Component
Treasury scarcity premium\"]\n A --> D[\"Supply/Demand
Hedging flows, issuance\"]\n A --> E[\"Regulatory
Balance sheet costs\"]\n B -->|\"Widens spread\"| F[\"Positive contribution\"]\n C -->|\"Can compress or invert\"| G[\"Negative contribution\"]\n D -->|\"Direction varies\"| H[\"Variable\"]\n E -->|\"Post-2008 effect\"| I[\"Compresses spread\"]\n`\n\nWhy Swap Spreads Went Negative (Post-2015):\n\nThe 30-year swap spread turned negative, meaning the swap rate was below the Treasury yield. This puzzled many because it implied the market was pricing interbank credit risk below sovereign credit risk.\n\nThe real explanation involves supply/demand dynamics:\n\nNumerical Example:\n\n| Component | 10-Year | 30-Year |\n|---|---|---|\n| Treasury yield | 4.25% | 4.60% |\n| Swap rate | 4.32% | 4.48% |\n| Swap spread | +7 bps | -12 bps |\n\nAt 30 years, the negative spread arises from:\n\n1. Corporate hedging demand: corporations issuing fixed-rate bonds swap to floating, creating massive demand to receive fixed in swaps. This pushes swap rates down.\n\n2. Treasury supply glut: government deficit spending floods the market with long-term Treasuries, pushing yields up.\n\n3. Balance sheet constraints: post-Dodd-Frank capital rules make it expensive for dealers to hold Treasury inventory, reducing their willingness to arbitrage the spread.\n\n4. Collateralization: swaps are now centrally cleared with daily margin, reducing counterparty credit risk to near zero. This eliminates the traditional credit premium.\n\nPractical Impact:\n\nTrader Vasilis at Clearwater Bank sees:\n- 10-year swap spread at +15 bps (historically low)\n- 30-year swap spread at -8 bps\n\nIf he believes supply/demand dynamics will normalize:\n- Pay fixed in 30-year swap + buy 30-year Treasury (bet on spread widening)\n- Risk: spread can remain negative or go more negative for years (\"the market can stay irrational longer than you can stay solvent\")\n\nFRM Exam Relevance:\nSwap spread analysis tests understanding of fixed income arbitrage limits, counterparty risk evolution, and regulatory impact on market microstructure. Know that negative swap spreads are not \"wrong\" -- they reflect structural market forces beyond simple credit risk.\n\nExplore interest rate risk topics in our FRM study resources.