Change in OI is today’s open interest at a strike minus its open interest at the previous session’s close. NSE’s chain labels it “Chng in OI” and places it next to open interest on both sides.
A positive change: more positions opened
A positive number means more contracts were opened than closed since the previous close. In the sample chain the largest addition on the call side is +52,587 contracts at 25,500, and on the put side +53,160 at 25,000.
What a negative change in OI means
A negative number means more contracts were closed than opened: buyers sold what they held and writers bought back what they had sold. Positions are being taken off; it is not a new bet in the other direction. The largest call reduction in the sample is −8,478 at 25,400, and the largest put reduction is −9,053 at 24,700.
| Change | Strike | Change in OI | OI now |
|---|---|---|---|
| Most calls added | 25,500 | +52,587 | 1,48,630 |
| Most puts added | 25,000 | +53,160 | 1,42,960 |
| Most calls closed | 25,400 | −8,478 | 88,450 |
| Most puts closed | 24,700 | −9,053 | 82,610 |
Read it with the price
On its own, change in OI says how many positions were added or removed, not by whom. The price change of the same contract tells you more. OI up with the price up is long buildup; OI up with the price down is short buildup; OI down with the price up is short covering; OI down with the price down is long unwinding. Each of the four is explained in OI buildup.
For example, the 25,500 call in the sample added 52,587 contracts while its price fell ₹25.45: that is short buildup.
Change in OI is not volume
Volume counts every contract that traded today. Change in OI counts only the net positions left over. At 25,500, 4,76,438 call contracts traded but open interest rose by 52,587: most of the day’s trading was existing positions changing hands or being opened and closed within the session.
Where the additions sit
Read change in OI across strikes, not one strike at a time. In the sample, the biggest call addition is 320 points above spot and the biggest put addition 180 points below it. Traders often describe that pattern as writers adding positions on both sides of the current level. It describes where positions were added today, not where the index will go.
Things to keep in mind
- Change in OI is measured from the previous close, so it starts again at zero every session.
- Rolling a position to the next expiry shows up as a fall in this expiry and a rise in the next one.
- Close to expiry, many positions are closed rather than held to settlement, which shows up as negative change in OI.
- Summing change in OI across strikes and comparing puts with calls gives a picture of the whole session, much like PCR does for open positions.
Related lessons
- Open interest (OI) in the option chain
- Long buildup, short buildup, short covering and long unwinding
- PCR (put-call ratio) in the option chain
Open the sample chain to select any number and read what it means.
Educational content, not investment advice. Every figure here comes from a synthetic sample chain, not live prices. See the terms of use.