What is Open Interest (OI)?
Open interest (OI) is the total number of derivative contracts, such as options or futures, that are open at a point in time and have not yet been squared off, exercised or expired. OI rises when a new buyer and a new seller open a position and falls when both close.
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What is OI in an option chain?
In an option chain, OI is shown for every strike, separately for the call and the put. The 24,600 CE OI is the number of 24,600 call contracts still open for that expiry. It does not tell you who is long or short, because every open contract has one of each. It tells you where money is committed.
What is the difference between OI and volume?
Volume counts every contract traded during the day, including positions opened and closed within minutes. OI counts only what is still open. A strike can trade huge volume and end the day with OI barely changed, which means traders were churning, not building positions.
What is put OI and call OI?
Call OI is the open contracts in call options at a strike; put OI is the open contracts in puts at the same strike. Since writers hold most index option OI in India, high put OI below the market is usually read as put writers expecting that level to hold, and high call OI above the market as call writers expecting a ceiling.
What if call OI is high?
High call OI at a strike above the market usually means resistance there. High call OI across many strikes above the market, with put OI thin, points to a bearish or capped market. What matters next is whether that call OI keeps growing (writers confident) or starts falling while price climbs (writers covering, often the start of a breakout).
How do you calculate OI?
The exchange calculates it. Each new contract where both sides are opening adds one to OI. A trade where one side opens and the other closes leaves OI unchanged. A trade where both sides close reduces it by one. NSE publishes OI through the session and the option chain picks it up.
How does AOC show OI?
Every OI cell shows the figure and its percentage of the largest OI on that side. The highest call OI gets a red box, the highest put OI a green box and the second highest on each side yellow. Tap an OI cell to see that strike's percentage graph through the day.
