CaseMark Bankruptcy Claim Interest Calculation
Calculates pre-petition interest and generates a defensible worksheet for attachment to a proof of claim.
Prerequisites
- Principal balance as of last payment or accrual date
- Annual interest rate and governing source (contract, judgment, or statute)
- Last payment date and petition date
- Underlying agreement (for day-count convention and fee authorization)
Quick Start
Per Diem = (Principal × Annual Rate) ÷ Day-Count Divisor
Pre-Petition Interest = Per Diem × Days (Last Payment → Petition Date)
Use the day-count divisor required by the contract or governing standard (e.g., 365 or 360).
Core Workflow
1. Determine Interest Rate
| Priority | Source | Notes |
|---|---|---|
| 1 | Contract rate | Express provision in loan agreement or note |
| 2 | Judgment rate | Rate from pre-petition judgment |
| 3 | State statutory | Applicable state prejudgment rate |
| 4 | Federal rate | 28 U.S.C. § 1961 (Treasury bill rate) |
Cite the source in the proof of claim with section number or statutory citation.
2. Select Day-Count Convention
| Convention | Divisor | Typical Use |
|---|---|---|
| Actual/365 | 365 | Consumer loans, mortgages (default if unspecified) |
| Actual/360 | 360 | Commercial loans, credit facilities |
| 30/360 | 360 (30-day months) | Bonds, commercial paper |
Follow the contract. Default to Actual/365 only when unspecified.
3. Calculate Interest
Simple interest (most common for bankruptcy claims):
Per Diem = (Principal × Annual Rate) ÷ Day-Count Divisor
Interest = Per Diem × Actual Days in Accrual Period
Total Claim = Principal + Interest + Authorized Charges
4. Apply Post-Petition Rules
| Claim Type | Post-Petition Interest? |
|---|---|
| Unsecured | No — stop at petition date (exception: solvent-debtor cases) |
| Secured (oversecured) | Yes — under § 506(b), to extent of equity cushion |
| Secured (undersecured) | No |
| Priority | No |
5. Verify Additional Charges
Late fees — include only if all apply:
- Contract expressly authorizes (cite section)
- Assessed pre-petition
- Not punitive or unconscionable
Attorney fees — include only if:
- Contract fee-shifting provision or statutory authorization
- Itemized statement attached (dates, hours, rates, descriptions)
- Pre-petition only; post-petition collection fees excluded
6. Complete Worksheet
═══════════════════════════════════════════════════════
INTEREST CALCULATION WORKSHEET
Case: [Debtor Name], Case No. [XX-XXXXX]
Creditor: [Creditor Name] Account No.: [Number]
═══════════════════════════════════════════════════════
PRINCIPAL
Original Debt Amount: $__________
Less: Payments Received: ($__________)
Principal Balance as of [Last Pmt Date]: $__________
INTEREST
Principal Balance: $__________
Annual Interest Rate: __________%
Rate Source: [ ] Contract §__ [ ] Judgment [ ] Statutory [ ] Federal
Accrual: [Last Pmt Date] → [Petition Date] = ____ days
Day-Count: [ ] Actual/365 [ ] Actual/360 [ ] 30/360
Per Diem = ($______ × ____%) ÷ _____ = $__________
Interest = $______ × ____ days = $__________
OTHER CHARGES
Late Fees (Contract §__): $__________
NSF/Returned Check Fees: $__________
Attorney Fees (see itemization): $__________
Other: ______________________: $__________
CLAIM SUMMARY
Principal: $__________
Pre-Petition Interest: $__________
Other Charges: $__________
───────────────────────────────────────────────────────
TOTAL CLAIM AS OF PETITION DATE: $__________
═══════════════════════════════════════════════════════
Prepared by: __________________ Date: _______________
Common Pitfalls
| Mistake | Fix |
|---|---|
| Post-petition interest on unsecured claim | Stop accrual at petition date |
| Wrong day-count divisor | Follow contract; default Actual/365 |
| Compounding on simple-interest contract | Match contract methodology exactly |
| Unauthorized late/attorney fees | Only include contractually or statutorily permitted charges |
| Using original loan amount as principal | Use balance after last credited payment |
| Missing rate citation | Always cite contract section or statute — unsupported rates invite objection |
Attach supporting documentation: rate source excerpt, payment history, fee authorization clause.
Key Authorities
- 11 U.S.C. § 502(b) — Allowance of claims; interest limitations
- 11 U.S.C. § 506(b) — Post-petition interest for oversecured creditors
- 28 U.S.C. § 1961 — Federal post-judgment interest rate