PCP Arbitrage Monitor (Math by Thomas)

Live monitor for Put–Call Parity (C + PV(K) = P + S) showing drift, arbitrage direction, and opportunity strength.

The PCP Arbitrage Monitor helps traders visualize and quantify deviations from the Put–Call Parity (PCP) relationship:

𝐶+𝐾𝑒−𝑟𝑇 = 𝑃+𝑆

When this equation drifts, it indicates a potential arbitrage opportunity between call, put, and underlying (spot or future).
This indicator plots the left-hand side (LHS) and right-hand side (RHS) of the PCP equation on your chart, computes the drift, and automatically highlights and displays actionable trade combinations when the deviation exceeds a set threshold.

⚙️ How It Works

Inputs

Call & Put Symbols – Select matching call and put options (same strike & expiry).
Strike (K) – The strike price for those options.
Expiry (UTC) – Option expiry date/time (used to calculate 𝑇 and PV(K)).
Risk-free Rate (r) – Annualized rate used for discounting the strike.
Lot Size / Tick Value – Used to calculate profit in INR.
Arbitrage Threshold – Minimum drift (in points) to trigger signals (default 200).
Displayed Data
LHS = C + PV(K) (Call + discounted Strike)
RHS = P + S (Put + Spot/Future)
Drift = LHS – RHS
Bookable Profit (INR)
Action Suggestion (only when |drift| ≥ threshold)
Background Highlight

🟩 Green – Call side expensive → Sell Call + Buy Put + Buy Fut

🟥 Red – Call side cheap → Buy Call + Sell Put + Sell Fut

Table
Displays all key values live in the top-right corner:
Option prices
LHS, RHS
Drift (points)
Time to expiry
Lot size
Bookable profit (INR)
Trade action (only if |drift| ≥ threshold)

📈 How to Use

Open a NIFTY Spot or Futures chart (works on both).
Enter the exact option symbols (e.g., NSE:NIFTY24DEC21900CE and NSE:NIFTY24DEC21900PE).
Adjust Strike (K) and Expiry to match those options.

Observe:

The green/red background highlights large deviations (≥ threshold).
The Action cell displays the arbitrage combination and expected profit.
A drift beyond the threshold suggests a potential risk-free arbitrage if executed simultaneously across all legs.
Hold positions till expiry if margin allows; the profit is theoretically locked in.

💡 Tips

Works on both Spot and Futures charts — the script auto-uses the chart’s close as 𝑆
Set smoothing to 0 to see raw parity values.
Adjust threshold based on costs and margin — e.g., 150–200 points for NIFTY is practical.
Only valid when options are European (no early exercise risk).
Ensure both option symbols are liquid and from the same expiry.

⚠️ Disclaimer

This tool is for educational and analytical purposes.
Real arbitrage execution depends on liquidity, bid-ask spread, slippage, and margin requirements.
Always validate prices with your broker before trading.