Understanding Open Interest (OI) – A Key to Options Market Sentiment

In derivatives trading, Open Interest (OI) plays a crucial role in gauging real-time market sentiment. 🔹 What is Open Interest? OI is the total number of active contracts (not squared off) in the market at a given strike price and expiry. It shows where the market participants are placing their bets. ✅ How to interpret OI changes: Price ↑ + OI ↑ = Long build-up (bullish) Price ↓ + OI ↑ = Short build-up (bearish) Price ↑ + OI ↓ = Short covering (bullish) Price ↓ + OI ↓ = Long unwinding (bearish) 📌 For Nifty/BankNifty, monitor highest OI levels in call & put options – these often act as resistance and support, respectively. 🧠 Example: If 22800 Call has the highest OI and Nifty is trading at 22700, expect resistance near 22800. If PCR (Put/Call Ratio) is below 0.8 → market is likely overbought Above 1.3 → oversold, bounce possible