# AI Mortgage-Underwriting Reproducibility + Disparate-Impact Snapshot

**== SAMPLE / GENERIC EXAMPLE -- SYNTHETIC DATA, NOT A CLIENT ENGAGEMENT ==**

**Format:** contrarianAI Independent-Verifier $499 Snapshot (v0.9 sensor)
**Snapshot generation date:** 2026-07-22
**Snapshot ID:** CAI-HS-GEN-DEMO-bcc166cae504a1f5e3cba06a

---

## 1. Scope of Snapshot

This SAMPLE Snapshot addresses a synthetic mid-market mortgage lender's AI-driven mortgage-underwriting classifier. Scenario details:

- **Lender profile:** ~$2B-$10B annual originations / mid-market bank OR non-bank IMB (independent mortgage banker)
- **AI system in scope:** mortgage-underwriting classifier (mock model version mortgage-underwriter-v4.7.2)
- **Audit period:** 2026-04-15 through 2026-07-13 (90 days)
- **Total applications analyzed:** 4,969
- **Baseline window:** first 30 days (1,572 applications)
- **Regulatory framework applied:**
  - Fair Housing Act 42 USC Sec 3601 et seq. (disparate-impact via HUD 24 CFR Sec 100.500)
  - Home Mortgage Disclosure Act 12 USC Sec 2801 et seq. (AI-decision reporting requirements 2026)
  - Equal Credit Opportunity Act 15 USC 1691 + Regulation B 12 CFR 1002
  - Fair Credit Reporting Act 15 USC 1681 (adverse-action notice)
  - CFPB Circular 2022-03 (AI in adverse-action notices)
  - CFPB Circular 2023-03 (AI-driven marketing UDAAP)
  - HUD Rule 24 CFR 100.500 (disparate-impact standard, 2023 reinstatement)
  - FHFA Advisory Bulletin AB 2021-01 (Enterprise AI/ML Standards)
  - OCC Bulletin 2011-12 + Federal Reserve SR 11-7 (Model Risk Management)
  - Dodd-Frank Sec 1400-1500 (Ability-to-Repay / Qualified Mortgage Rule)
  - State licensed-lender AI-decisioning laws (CA, NY, MA, CO, IL active 2025-2026)
  - FTC Section 5 (unfair/deceptive practices, applies to non-bank lenders)

---

## 2. Sensor summary

- **Sensor version:** contrarianAI-distsensor-v0.9
- **Sensor family:** distributional-shape (independent of production model family)
- **Independence:** sensor operates on the mortgage-underwriting AI's output stream only. Distinct from the production model family. Different mathematical basis (distributional-shape statistics vs gradient-boosted classifier). Different retention pipeline. contrarianAI holds no equity, employment, or vendor relationship with any mortgage-tech vendor (ICE / Blend / Rocket Logic / Zest AI / Upstart / Stavvy / SnapLogic or any similar).

- **Detection thresholds active:**
  - Mean-shift threshold: 1.5 standard deviations from baseline
  - Variance-ratio threshold: 1.5x baseline
  - KL-divergence threshold: 0.2
  - Cohort disparate-impact differential threshold: 12% shift across cohorts

---

## 3. Findings summary

- **Total drift events detected:** 11
- **High severity:** 10
- **Medium severity:** 1
- **First drift day (post-baseline):** Day 30
- **Critical disparate-impact-differential signal flagged:** NO

---

## 4. Overall determination

**CATEGORY C -- INSUFFICIENT FOR ATTESTATION**

Multiple high-severity distributional-drift events detected in the AI mortgage-underwriting engine across the audit period. Lender should not represent the mortgage-underwriting AI as Fair Housing Act-defensible, HMDA-reportable-accurate, or CFPB-exam-ready until named remediation completes and independent re-audit confirms closure.

---

## 5. The 3 fix-first items scoped to this AI surface

1. **Freeze or hold-for-manual-underwriting-review** all post-drift AI mortgage decisions in Cohort H3 pending Fair Housing Act + ECOA disparate-impact validation. Document the pause + resumption criteria in the Compliance Management System. Notify CRA/Fair-Lending Officer + Chief Compliance Officer + General Counsel.
2. **Retain evidence artifacts** for every application in the audit period -- model version pin, application data snapshot, credit-bureau snapshot, property-valuation methodology, AVM inputs, underwriting-risk-score, lane routed, decision hash. Retention per SR 11-7 Sec V.B model documentation + HMDA Sec 304 record-retention + CFPB Circular 2022-03 adverse-action reason-code accuracy. Deletion holds should be issued now for any potential HUD/DOJ/CFPB inquiry.
3. **Add adaptive drift-monitoring** to production mortgage-underwriting pipeline. Annual OCC/SR 11-7 model-risk-management review alone is insufficient given the between-audit blind spot where CFPB supervisory examinations, DOJ fair-lending referrals, HUD complaint filings, and class-cert findings compound. Real-time cohort-differential monitoring is the operational fix.

---

## 6. Detailed drift events

Each event includes date, sensor type, affected applicant cohort, severity, and plain-language detail describing what the sensor observed in the mortgage-underwriting AI's decision stream.

### Day 30 (2026-05-15) -- cohort_distribution_divergence (cohort H5)
- **Severity:** high
- **Detail:** Cohort H5 score distribution shape has diverged from baseline (KL=0.798). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.7978

### Day 37 (2026-05-22) -- cohort_distribution_divergence (cohort H5)
- **Severity:** high
- **Detail:** Cohort H5 score distribution shape has diverged from baseline (KL=0.523). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.5227

### Day 44 (2026-05-29) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.833). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.8329

### Day 51 (2026-06-05) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.834). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.8337

### Day 58 (2026-06-12) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.810). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.8097

### Day 65 (2026-06-19) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.963). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.9632

### Day 72 (2026-06-26) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.894). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.8938

### Day 79 (2026-07-03) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.901). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.901

### Day 79 (2026-07-03) -- cohort_distribution_divergence (cohort H5)
- **Severity:** high
- **Detail:** Cohort H5 score distribution shape has diverged from baseline (KL=0.819). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.8192

### Day 86 (2026-07-10) -- cohort_distribution_divergence (cohort H3)
- **Severity:** high
- **Detail:** Cohort H3 score distribution shape has diverged from baseline (KL=0.944). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.9436

### Day 86 (2026-07-10) -- cohort_distribution_divergence (cohort H5)
- **Severity:** medium
- **Detail:** Cohort H5 score distribution shape has diverged from baseline (KL=0.337). Bimodal-emergence or long-tail-shift likely.
- **KL-divergence:** 0.3372

---

## 7. Counterparty-question rehearsal

**CFPB supervisory-exam + DOJ fair-lending-referral + HUD complaint-response question the lender's own compliance counsel would demand:**

> "Reproduce this AI-generated mortgage-underwriting decision from Day 47 including the applicant's stated purpose, credit bureau snapshot, property valuation methodology, model version, underwriting-risk-score, and lane routed -- as a defensible record we can produce for CFPB supervisory examination, DOJ fair-lending referral, HUD complaint response, state banking-department examination, or class-cert opposition."

**Sample application decisions from Day 47:**

| Application ID | Risk Score | Lane | Model Version | Decision Hash |
|----------------|------------|------|---------------|---------------|
| LA-002534 | 44.17 | Manual Review + Upcharge | mortgage-underwriter-v4.7.2 | `muw-002534` |
| LA-002533 | 82.1 | Decline / Refer non-QM | mortgage-underwriter-v4.7.2 | `muw-002533` |
| LA-002532 | 70.1 | Decline / Refer non-QM | mortgage-underwriter-v4.7.2 | `muw-002532` |
| LA-002531 | 86.36 | Decline / Refer non-QM | mortgage-underwriter-v4.7.2 | `muw-002531` |
| LA-002525 | 51.16 | Manual Review + Upcharge | mortgage-underwriter-v4.7.2 | `muw-002525` |

**Reproduction status:** all 5 sampled Day-47 application decisions can be reproduced with defensible-records match: model version pinned (mortgage-underwriter-v4.7.2 / training cutoff 2026-01-15), decision hash cryptographically bound, input data (applicant cohort + loan product + property type + loan amount + credit tier + LTV + DTI at application-time) retained via decision-provenance record. Full inputs available via decision_hash lookup in the executable-action ledger (AIC layer #7) + time-of-decision knowledge snapshot (AIC layer #8).

**Retention:** artifacts retained per HMDA Sec 304 record retention + SR 11-7 model-documentation horizon (life of model + 3 years post-decommission) + CFPB Circular 2022-03 adverse-action-reason accuracy preservation duty.

---

## 8. What full Enterprise Attestation adds beyond this Snapshot

This $499 Snapshot addresses ONE AI system (mortgage-underwriting classifier) at the SAMPLE lender. A full Enterprise Attestation ($35-55K / 3-6 weeks) covers:

- **All 8 AIC layers** (this Snapshot covers layers 1-4 + 6; Enterprise adds layers 5, 7, 8)
- **Full AI surface inventory** (mortgage-underwriting + AVM + tenant-screening + loss-mitigation + collections + servicing-decisioning + fraud-scoring + marketing-audience-generation -- every AI-touched surface)
- **Signed regulator-facing attestation deliverable** (this Snapshot = internal-use PDF; Enterprise = signed statement suitable for CFPB supervisory-exam response, OCC/FRB safety-and-soundness exam, HUD complaint reply, DOJ fair-lending referral defense, state banking-department examination, board-of-directors quarterly-risk report, or investor/counterparty due-diligence production)
- **On-site scoping session with your team** (this Snapshot = data-driven only; Enterprise = on-ground with your Chief Compliance Officer + General Counsel + Chief Risk Officer + Model Risk Management head + Fair Lending Officer + CIO)
- **30/60/90 remediation roadmap w/ named owners + milestones**
- **Adaptive drift-monitoring implementation guidance**
- **Re-audit cadence recommendation tied to your HMDA LAR + CFPB exam calendar**

**Baseline Audit ($2,500 / 5 days) is the intermediate tier** -- gap map + measurable test + 30/60/90 roadmap on ONE AI surface. Snapshot credit applies to Baseline OR Enterprise upgrade within 30 days.

**Big-4-equivalent context:** Deloitte / PwC / EY / KPMG fair-lending-audit engagements + model-risk-management review typically price $200K-$1M+ for equivalent Enterprise scope. contrarianAI delivers the same determination shape + regulator-facing attestation at 5-10% of that price via independent-verifier positioning + tooling-driven delivery.

---

## 9. Independent-verifier declaration

I, Kevin Luddy, as principal of contrarianAI LLC, personally attest that:

1. contrarianAI is not an employee, contractor, equity holder, or vendor of the audited lender or any of its mortgage-tech vendors (ICE, Blend, Rocket Logic, Zest AI, Upstart, Stavvy, Encompass, Byte, Calyx, LendingQB, or any similar).
2. Assessment tools (distributional-shape sensor, retrieval-auditor, tool-call-grader, prompt-drift-sensor, predictor-corrector, router-drift-sensor) use model families and evaluation methods distinct from those in production at the audited lender.
3. This Snapshot is based on the data-sample submitted by the buyer. Changes to the audited lender's infrastructure after the Snapshot date are outside this Snapshot's scope.
4. Underlying audit evidence is retained for the Snapshot horizon and will be made available for legitimate regulatory / audit / counterparty inquiry (CFPB, OCC, FRB, FDIC, NCUA, HUD, DOJ, state banking department, GSE, or counterparty investor) with appropriate legal process.

**Signed:** Kevin Luddy, Principal, contrarianAI LLC
**Date:** 2026-07-22
**Retention key:** `bcc166cae504a1f5e3cba06a`

---

## 10. Charts + artifacts

- `chart_hs_distributional_drift.png` -- 7-day rolling mean underwriting-risk-score per applicant cohort over the 90-day period
- `chart_hs_baseline_vs_drifted.png` -- Cohort H3 baseline vs recent underwriting-risk-score distribution (largest observed drift)
- `chart_hs_lane_shift.png` -- Underwriting-lane rate per cohort, baseline vs recent
- `hs_drift_analysis.json` -- machine-readable analysis + event metadata
- `hs_dataset.csv` -- synthetic 90-day mortgage-application input data
- `hs_agent_decisions.csv` -- mortgage-underwriting AI output + scored underwriting decisions

---

*End of Snapshot CAI-HS-GEN-DEMO-bcc166cae504a1f5e3cba06a*

**== END OF SAMPLE -- YOUR ACTUAL $499 SNAPSHOT WILL LOOK STRUCTURALLY IDENTICAL BUT WITH YOUR LENDER'S DATA + AI SYSTEM + STATE/CHARTER FOOTPRINT + REGULATORY-FRAMEWORK CITATIONS ==**

---

## To purchase YOUR lender's $499 Snapshot:

1. Visit: **contrarianai-landing.onrender.com/housing-snapshot.html**
2. Click **Buy $499** -- Stripe direct-buy, no procurement approval
3. Complete intake form (~2 min): name your AI system + submit 100-1000 anonymized mortgage-decision records
4. Report PDF delivered via email within 3 business days

**Snapshot credit ($499) applies to upgrade within 30 days:**
- **Baseline Audit** ($2,500 / 5 days) -- Snapshot credit = $499 off
- **Enterprise Attestation** ($35-55K / 3-6 weeks) -- Snapshot credit = $499 off

Book a call: **cal.com/kevin-luddy-0dlzuu**