Equity Models : Quant Interview Playbook

Most aspiring quants don’t struggle with equity models because they lack math.

They struggle because they can’t connect models to PnL, hedging, and real desk decisions.

You may know:

Black–Scholes assumptions

Heston equations

Local volatility formulas

But interviews and desks ask different questions:

Why does delta hedging bleed?

Why do barriers misprice under local vol?

Why does skew dominate PnL in crashes?

Which model breaks first — and how do you detect it?

This guide is built to answer those questions.

📘 What this guide focuses on

This is not a formula-heavy textbook.

This is a model-thinking and PnL-first guide for equity desks and interviews.

You’ll learn:

Why equity skew is structural (not incidental)

How volatility, skew, vanna, and jumps drive real PnL

Why desks knowingly use “wrong” models

How to choose models based on dominant risk — not elegance

🧠 Models Covered (with intuition + consequences)

Black–Scholes — why it fails, why it still survives

Local Volatility (Dupire) — perfect fit, broken dynamics

Stochastic Volatility (Heston) — skew, vol-of-vol, hedging stability

Jump Models (Merton / Bates) — earnings gaps & crash risk

Local–Stochastic Vol (LSV) — the desk compromise model

Each model is explained via:

assumptions → equations → calibration → Greeks → PnL → failure modes

📊 What makes this guide different

✔ Master Equity Model Map (one-glance comparison of all models)

✔ Explicit PnL attribution: delta, gamma, vega, skew, vol-of-vol

✔ Model failure signatures (how to detect when your model is wrong)

✔ Real desk-style case studies (barriers, autocalls, crash regimes)

✔ Interview-ready language, not academic phrasing

✔ Clear explanation of why residual PnL ≠ trader error

🎯 Who this is for

Aspiring Equity Desk Quants

Derivatives Traders who want model intuition

Risk / Model Validation / XVA Quants

Candidates preparing for front-office interviews

If you already know the math but struggle to explain models like a practitioner, this guide closes that gap.

🎟️ Coupon Code

Use EQUITIES10 to get 10% off

⚠️ Disclaimer

These notes are for educational and informational purposes only.

They do not constitute financial advice, trading recommendations, or investment guidance.

Models and examples are simplified for learning and interview preparation and may differ from proprietary implementations used by financial institutions.

All intellectual property is owned by the author. Redistribution or resale is strictly prohibited.