Options Greeks in Practice

1. The Dashboard Metaphor — Reading Your Greeks

Think of options Greeks as your trading dashboard, not a formula sheet. When you buy or sell an option, you're simultaneously taking on five exposures at once. Each Greek is a dial that tells you how much your P&L will change as one input moves.

In this article we'll focus on Delta, Gamma, Theta, and Vega — the four that dominate most real-world options positions. Rho matters mainly for LEAPS and longer-dated instruments.

2. The Four Greeks — Intuition First

3. Delta — Managing Directional Exposure

Delta is your most important real-time risk number. Professionals track dollar delta — not just the dimensionless Greek, but how much cash you'd make or lose on a 1% stock move.

Dollar Delta = Δ × Lot Size × Stock Price × Number of Contracts

Example:
  RELIANCE ATM call: Δ = 0.50, lot = 250, price = ₹2,800, 2 contracts

  Dollar Delta = 0.50 × 250 × ₹2,800 × 2 = ₹7,00,000

This means: RELIANCE moves 1% → your option book moves ≈ ₹7,000
(because 1% of ₹7L exposure = ₹7,000)

Delta Hedging

To be delta-neutral — to not care about direction and only trade vol — you offset your option delta with stock or futures.

# Delta neutral hedge

option_delta = 0.60      # long 1 NIFTY call, delta 0.60
lot_size     = 50        # NIFTY lot
contracts    = 10        # 10 lots

total_delta = option_delta * lot_size * contracts  # = 300

# To hedge: short futures equal to total delta
# 1 NIFTY future = 50 delta
futures_to_short = total_delta / lot_size  # = 6 lots of futures

print(f"Long {contracts} CE lots → {total_delta} delta exposure")
print(f"Short {futures_to_short} futures → portfolio delta = 0")
print(f"Now P&L driven purely by Gamma, Theta, Vega")

Delta Across Strike Prices

4. Gamma — Convexity Is Everything

Gamma is why options buyers love big moves and options sellers fear them. It's the source of "convexity" — the non-linearity that makes options fundamentally different from stocks.

P&L due to Gamma ≈ ½ × Γ × (ΔS)²

Example:
  Long straddle, Gamma = 0.05 (per ₹1 move)
  NIFTY moves 200 pts in one day

  Gamma P&L = ½ × 0.05 × 200² = ½ × 0.05 × 40,000 = ₹1,000 per unit

This is in ADDITION to the linear Delta P&L.
The (ΔS)² term is why buyers love big moves — gains are convex, losses are capped.

5. Theta vs Gamma — The Central Trade-off

Here's the core insight that professional options traders live by: Theta and Gamma are always in opposition. You cannot have both positive Gamma (convexity) and positive Theta (time decay working for you) unless you are doing something very exotic.

This explains why options selling strategies (collecting Theta) are not "free money." You're short Gamma — you're exposed to blow-up risk from large moves. The historical win rate looks great, but the occasional blowout is the price.

6. Vega — Trading Volatility Itself

Vega is your exposure to changes in implied volatility (IV) — the market's forecast of future stock volatility. This is separate from realised vol. IV is driven by supply/demand for options (fear, events, uncertainty).

Dollar Vega = Vega × Contracts × Lot Size

Change in option value ≈ Vega × ΔIV (in percentage points)

Example:
  Long 5 NIFTY straddles (ATM), Vega per straddle = ₹250
  IV jumps from 15% to 20% (+5 points) ahead of RBI policy

  Vega P&L = ₹250 × 5 × 5 = ₹6,250 gain
  (this is BEFORE any move in NIFTY itself)

7. Greeks as a Portfolio — Net Exposure

Professional options desks track net Greeks across the entire book, not per position. The sum tells you your aggregate risk.

Reading this book: net delta is −3.11 (slightly net short), long Gamma (+0.05 — benefits from big moves), paying Theta (−₹220/day), and long Vega (+₹290 — benefits if IV rises). This is a long volatility bias — expects a move or IV spike, pays ₹220/day for that view.