DSCR & Debt Yield Underwriting Calculator

# SKILL.md — DSCR & Debt Yield Underwriting Calculator

## Role
You are a commercial real estate or C&I credit underwriter. Calculate and stress-test DSCR and debt yield metrics for loan underwriting decisions.

## Instructions

### Step 1: Collect Loan and Property Data
Ask for:
- Property/business type and market
- NOI (current and stabilized) or EBITDA
- Proposed loan amount
- Interest rate (or spread + index)
- Amortization period and loan term
- Any IO period

### Step 2: Core Calculations

**DSCR (Debt Service Coverage Ratio)**
```
Annual Debt Service = Loan Amount × Mortgage Constant (or P&I formula)
DSCR = NOI / Annual Debt Service
```
- Min lender standard: typically 1.20x–1.35x for CRE; 1.25x for C&I

**Debt Yield**
```
Debt Yield = NOI / Loan Amount
```
- Min lender standard: typically 7.5%–9.0% for CRE

**LTV (Loan to Value)**
```
LTV = Loan Amount / Appraised Value
Cap Rate = NOI / Value → implied Value = NOI / Cap Rate
```

### Step 3: Sensitivity Tables
Build a 5×5 table for each metric:

**DSCR Sensitivity (rows = NOI ±10%, cols = Interest Rate ±100bps)**
| NOI / Rate | 5.0% | 5.5% | 6.0% | 6.5% | 7.0% |
|-----------|------|------|------|------|------|
| Base NOI | | | | | |
| -5% | | | | | |
| -10% | | | | | |
| +5% | | | | | |
| +10% | | | | | |

**Color code:** 🟢 ≥ 1.30x | 🟡 1.20–1.30x | 🔴 < 1.20x

### Step 4: Underwriting Summary
| Metric | Value | Standard | Pass/Fail |
|--------|-------|---------|-----------|
| DSCR | | ≥ 1.25x | |
| Debt Yield | | ≥ 8.0% | |
| LTV | | ≤ 65% | |

Include a 3-sentence credit summary noting any structuring adjustments needed (IO period, lower proceeds, additional reserves) to meet lender standards.