How is replacement cost calculated under SA-CCR, and how does margining affect the computation?

SA-CCR (Standardized Approach for Counterparty Credit Risk) computes Exposure at Default as:\n\nEAD = alpha x (RC + PFE)\n\nwhere alpha = 1.4 (regulatory multiplier). The replacement cost (RC) component captures current exposure, and its formulation differs based on whether the netting set has a margin agreement.\n\nUnmargined RC:\n\nRC = max(V - C, 0)\n\nwhere V = current mark-to-market value of the netting set and C = net collateral held. This is simply the current positive exposure after netting collateral.\n\nMargined RC:\n\nRC = max(V - C, TH + MTA - NICA, 0)\n\nwhere:\n- TH = threshold (exposure level before margin call is triggered)\n- MTA = minimum transfer amount\n- NICA = net independent collateral amount (initial margin held minus initial margin posted)\n\n`mermaid\ngraph TD\n A[\"Netting Set\"] --> B{\"Margin Agreement?\"}\n B -->|\"No\"| C[\"RC = max(V - C, 0)\"]\n B -->|\"Yes\"| D[\"RC = max(V - C,
TH + MTA - NICA, 0)\"]\n C --> E[\"Captures: current MTM exposure\"]\n D --> F[\"Captures: exposure that can
build before margin is received\"]\n E --> G[\"EAD = 1.4 x (RC + PFE)\"]\n F --> G\n`\n\nWorked Example:\nPinnacle Derivatives has a netting set with Evergreen Bank:\n\n| Parameter | Value |\n|---|---|---|\n| Portfolio MTM (V) | +$14.2 million |\n| Variation margin held (C) | $12.8 million |\n| Threshold (TH) | $1.0 million |\n| Minimum transfer amount (MTA) | $0.5 million |\n| Initial margin held (IM received) | $5.0 million |\n| Initial margin posted (IM posted) | $0.0 million |\n| NICA | $5.0 million |\n\nMargined RC = max(14.2 - 12.8, 1.0 + 0.5 - 5.0, 0)\n= max(1.4, -3.5, 0)\n= $1.4 million\n\nThe RC picks up the $1.4 million gap between MTM and variation margin. The TH + MTA - NICA term is negative (excess initial margin provides a buffer), so the first term governs.\n\nIf the portfolio had no margin agreement:\nUnmargined RC = max(14.2 - 0, 0) = $14.2 million (ten times larger).\n\nWhy the Margined Formula Has a Floor:\nThe TH + MTA - NICA floor represents the maximum exposure that could accumulate between margin calls. Even if current MTM is fully collateralized, the threshold and MTA allow some exposure to build before a margin call triggers. Initial margin (NICA) offsets this gap.\n\nPractical Implications:\n- Banks with higher thresholds in their CSAs face higher RC and thus higher capital charges\n- Posting initial margin (reducing NICA) directly reduces RC\n- The alpha multiplier of 1.4 adds a 40% buffer for model risk and wrong-way risk\n\nStudy SA-CCR in detail with our FRM Part II materials.