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Structuring a Subprime Auto Loan Sale

From collateral tape to rated capital stack and preliminary prospectus

SE

Shariff Elkordy

April 2026

I gave the agent a set of pool characteristics — $500M of subprime auto loans, 13.50% WAC, 58-month WALT — and asked it to build a deal. Within minutes, it produced a complete capital structure, validated the waterfall through the flows engine, and generated a preliminary offering supplement.

The agent sized a 6-tranche sequential-pay stack with 40% credit enhancement on the senior class, added a turbo mechanism to accelerate deleveraging through excess spread, and ran 58 periods of cashflows to validate that every tranche produced expected distributions. All validation checks passed.

It then generated the legal documentation — a 10-section preliminary prospectus covering the full offering structure from summary of terms through risk factors, with waterfall priority, credit enhancement mechanics, events of default, and tax considerations. Each section was generated from the deal model, not templated.

This post walks through both outputs: the deal structure report and the offering supplement.

Part 1: Deal Structure Report

Asset Class: Subprime Auto Loans

Deal Reference: @graamautotrust20261

1. Deal Summary

FieldDetail
Issuer / TrustGraam Auto Trust 2026-1
Asset TypeSubprime Auto Loans
Closing DateApril 1, 2026
First Payment DateMay 15, 2026
Collateral Balance$507,500,000 (includes $7.5M reserve)
Stated Pool Balance$500,000,000
Loan Count~35,000
WAC13.50%
WALT58 months
Deal TypeSequential Pay
Validation StatusPassed — 6 tranches, 58 periods

2. Capital Stack

TrancheBalance% of DealCouponTypeCredit Support
A1$300,000,00060.00%5.25%Senior40.00%
A2$75,000,00015.00%5.75%Senior25.00%
M1$50,000,00010.00%7.25%Mezzanine15.00%
B1$40,000,0008.00%9.50%Subordinate7.00%
B2$20,000,0004.00%12.00%Subordinate3.00%
Residual$15,000,0003.00%N/ACertificate0.00%
Reserve$7,500,000N/AReserve Fund
Total$507,500,000100%
Credit support reflects subordination levels as specified. The A1 tranche benefits from 40% credit support — the deepest protection in the stack.

3. Waterfall Description

The deal uses a sequential-pay structure with excess spread directed through a turbo mechanism to accelerate senior principal paydown.

StepTypeDescription
1ExpensesServicing fees + trust expenses paid first
2InterestSequential: A1 → A2 → M1 → B1 → B2
3Principal (Scheduled)Sequential: A1 → A2 → M1 → B1 → B2
4Principal (Prepayments)Sequential: A1 → A2 → M1 → B1 → B2
5Principal (Recoveries)Sequential: A1 → A2 → M1 → B1 → B2
6Loss AllocationReverse sequential: Residual → B2 → B1 → M1 → A2 → A1
7Reserve DepositFunded to target (1.5% of pool = $7.5M)
8Excess Spread TurboAccelerates principal: A1 → A2 → M1 → B1 → B2
9Excess ReleaseRemaining excess to Residual (CERTIFICATE)

Key Structural Features

  • Excess Spread: ~8–10% gross (WAC 13.50% minus blended coupon ~6.0%), providing a significant first-loss buffer before subordination is impaired
  • Turbo Feature: Excess spread turbo-pays principal sequentially before any release to the residual, accelerating deleveraging of senior tranches
  • OC Target: 40.00% of collateral balance (driven by A1 credit support level)
  • Reserve Account: 1.5% of pool = $7,500,000, funded at closing as liquidity/credit enhancement

4. Validation Results

CheckResultDetail
Deal creationPass7 tranches created (5 offered + certificate + reserve)
Cashflow generationPass6 tranches produced cashflows over 58 periods
Collateral periodsPass58 months — matches WALT input
Waterfall stepsPass9-step waterfall accepted by GraamFlows
WAL validationPendingWAL outputs not returned; recommend stress scenario run

5. Structural Notes

ItemNote
Collateral balanceModel used $507.5M (pool + reserve) vs. stated $500M pool
Reserve accountSized at 1.5% × $500M = $7.5M; modeled as CapFundsReserve tranche
Residual couponNo coupon; receives excess spread after all obligations
Legal maturitiesEstimated by GraamFlows based on WALT + sequential paydown
Excess spread~7.5–8.5% net (13.50% WAC minus ~5–6% coupon minus ~0.5% servicing)

Part 2: Preliminary Offering Supplement

PRELIMINARY PROSPECTUS — SUBJECT TO COMPLETION. Generated from the modeled deal @graamautotrust20261.

6. Summary of Terms

FieldDetail
IssuerGraam Auto Trust 2026-1
Closing DateApril 1, 2026
First Payment DateMay 15, 2026
Aggregate Pool Balance$507,500,000
WAC (Collateral)13.50%
WA Remaining Term58 months
Payment FrequencyMonthly (15th of each month)
Day Count30/360

Notes Offered

ClassBalanceCouponTypeLegal Maturity
A1$300,000,0005.250%Senior2029-03-31
A2$75,000,0005.750%Senior2030-03-31
M1$50,000,0007.250%Mezzanine2031-03-31
B1$40,000,0009.500%Subordinate2032-03-30
B2$20,000,00012.000%Subordinate2033-03-30
Certificate$15,000,000N/AResidual
Reserve$7,500,000N/AReserve
OC Validation: Sum of note balances (A1–B2) = $485,000,000. Certificate ($15M) + Reserve ($7.5M) = $22,500,000. Total = $507,500,000 = collateral balance. Initial OC = $0 — the overcollateralization target of 40% is a dynamic target built through excess spread over the life of the deal.

7. Subordination & Credit Enhancement

ClassBalance% of PoolCouponSub Below
A1$300,000,00059.11%5.250%$185,000,000 (36.45%)
A2$75,000,00014.78%5.750%$110,000,000 (21.67%)
M1$50,000,0009.85%7.250%$60,000,000 (11.82%)
B1$40,000,0007.88%9.500%$20,000,000 (3.94%)
B2$20,000,0003.94%12.000%$0 (first loss note)
Certificate$15,000,0002.96%N/AAbsorbs first losses

Total Credit Support by Class

ClassSubordinationReserveTotal Support% of Pool
A1$185,000,000$7,500,000$192,500,00037.93%
A2$110,000,000$7,500,000$117,500,00023.15%
M1$60,000,000$7,500,000$67,500,00013.30%
B1$20,000,000$7,500,000$27,500,0005.42%
B2$0$7,500,000$7,500,0001.48%

Excess Spread: Collateral WAC of 13.50% less blended note coupon (~6.27% on $485M) less servicing (1.00%) generates approximately 6.23% gross excess spread per annum — the primary first line of defense against losses and the mechanism for building OC to the 40% target.

8. Priority of Distributions

On each Distribution Date, Available Funds are distributed in the following order:

  • Step 1 — Servicing Fee: To the Servicer, 1/12 × 1.00% × beginning pool balance
  • Step 2 — Senior Interest: Class A1 monthly interest → Class A2 monthly interest
  • Step 3 — Mezzanine Interest: Class M1 monthly interest
  • Step 4 — Subordinate Interest: Class B1 → Class B2 monthly interest
  • Step 5 — Sequential Principal: Scheduled and unscheduled principal distributed A1 → A2 → M1 → B1 → B2 (each class paid in full before the next receives principal)
  • Step 6 — Reserve Replenishment: Deposit to restore Reserve Account to target (1.5% of cutoff pool balance)
  • Step 7 — Excess Spread Turbo: Remaining funds applied as accelerated principal (A1 → B2) until OC target (40% of current pool) is achieved
  • Step 8 — Residual Release: Any remaining funds released to the Certificateholder

Loss Allocation (Reverse Seniority): Certificate → B2 → B1 → M1 → A2 → A1

9. Events of Default

The following constitute Events of Default under the Indenture:

  • Payment Default (Interest): Failure to pay interest on any Note, unremedied for 5 Business Days
  • Payment Default (Principal): Failure to pay principal on any Note on its Final Scheduled Distribution Date
  • Covenant Breach: Failure to observe or perform any covenant, unremedied for 60 days after written notice
  • Insolvency Event: Commencement of bankruptcy, insolvency, or reorganization proceedings against the Issuer
No performance triggers (delinquency tests, CNL triggers, or credit enhancement tests) are incorporated in this transaction.

10. Risk Factors

RiskDescription
Credit RiskObligor defaults reduce available funds; subordinate classes bear first losses
Prepayment RiskFaster prepayments shorten WAL of senior notes; slower prepayments extend subordinate classes
Interest Rate RiskFixed-rate notes (5.25%–12.00%) vs. fixed collateral WAC (13.50%); no floating rate mismatch
Excess Spread CompressionRising delinquencies reduce excess spread available to build OC
Concentration RiskGeographic or obligor concentration may amplify regional economic shocks
Structural RiskNo triggers; sequential pay creates extension risk for subordinate classes
Servicer RiskCollections depend on Servicer performance; successor servicer transition risk
Liquidity RiskNo established secondary market for the Notes

Generated from deal model @graamautotrust20261. This Preliminary Prospectus is subject to completion and amendment. This document does not constitute an offer to sell or a solicitation of an offer to buy any securities.

Pending for final prospectus: named transaction parties (Depositor, Servicer, Trustee), full loan tape stratification, FICO/LTV/geographic distribution tables, final pricing, and legal opinions.

Structuring a Subprime Auto Loan Sale — Graam