Section 3 · Activity
Open interest and volume
Three columns count contracts, not money: how many traded today, how many are still open, and how that number changed.
Sample Indexspot 4,865.00previous close 4,851.00expiry in 14 dayslot 45 unitsall figures invented
| Calls | Puts | |||||||
|---|---|---|---|---|---|---|---|---|
| OI | Chng in OI | Volume | Strike | Volume | Chng in OI | OI | ||
| call in the money | 22,550 | 0 | 17,200 | 4,700 | 31,000 | 0 | 40,600 | |
| call in the money | 39,950 | +1,450 | 37,250 | 4,750 | 67,100 | −1,450 | 71,900 | |
| call in the money | 27,200 | +2,900 | 32,600 | 4,800 | 58,700 | −2,900 | 49,000 | |
| call in the money | 30,400 | +4,350 | 50,850 | 4,850 | 91,550 | −4,350 | 54,700 | |
| 52,300 | −4,350 | 75,550 | 4,900 | 41,950 | +4,350 | 29,050 | put in the money | |
| 47,050 | −2,900 | 50,600 | 4,950 | 28,150 | +2,900 | 26,150 | put in the money | |
| 69,300 | −1,450 | 59,400 | 5,000 | 33,000 | +1,450 | 38,500 | put in the money | |
| 39,250 | 0 | 27,950 | 5,050 | 15,500 | 0 | 21,800 | put in the money | |
Excerpt: the activity columns on each side.
On a narrow screen this table scrolls sideways; the strike column is in the middle.
Volume
The number of contracts traded during the session. Each trade has a buyer and a seller and counts once. In the specimen the 4,850 put traded 91,550 contracts.
Open interest
The number of contracts still open at the end of the session: positions that have been opened and not yet closed or expired. Every open contract has one holder and one writer, so open interest counts contracts, not people and not directions.
Change in open interest
Today's open interest minus yesterday's. It moves in three ways:
- Up when a trade opens a new position for both buyer and seller.
- Down when a trade closes an existing position for both.
- Unchanged when one side closes and passes the position to someone opening it.
That is why volume can come with little or no change in open interest: in the specimen the 5,050 call traded 27,950 contracts while its open interest changed by 0.