Fast, just like a weekly option. With 6 calendar days left, it has as much time as a NIFTY weekly on its Wednesday. Take an at-the-money call, whose strike is closest to the index. If nothing moves, it keeps about 57% of Wednesday's price by Monday's open. About 37% is left when expiry day opens.
- Index
- BANKNIFTY
- Cycle
- BANKNIFTY monthly
- Starts
- 09:15 IST
- Runs for
- 5 trading days · About 1 hr 37 min at Normal speed
- Difficulty
- Intermediate
- Date
- 19 Aug 2026
- Expiry
- BANKNIFTY 25 Aug 2026
- IV
- 13.88%
What is this market shaped like?
The market starts on the Wednesday before the monthly expiry. It runs Wednesday, Thursday, Friday, Monday and the expiry Tuesday. For BANKNIFTY, a night counts as about 0.4 of a trading day and a weekend as about 0.8.
What is left of an at-the-money call's price, if nothing moves
| When | Left of Wednesday's opening price |
|---|---|
| Wednesday open | 100% |
| Wednesday close | 93% |
| Friday close | 68% |
| Monday open | 57% |
| Tuesday open | 37% |
Nothing moves means the index stays still and IV stays the same. IV (implied volatility) is the size of move option prices expect.
A NIFTY weekly follows almost the same path from its own Wednesday.
What will you see?
- Theta, the value lost to time, now takes a big share each day.
- On Wednesday, 1 day of time is worth about 61 points of BANKNIFTY. The index must rise that much by the close to pay for it.
- Delta is how much an option moves for each point the index moves. Gamma is how fast delta changes. Gamma grows near the money as expiry gets close.
What should you try?
Try this with 1 lot of 1 call. A lot is the smallest size you can trade.
- Buy 1 lot of the at-the-money call at Wednesday's open.
- Hold it to Tuesday and note its price at each close.
- Compare your prices with the table.
What should you check afterwards?
- Which took the most: Wednesday, the weekend or Monday?
- How far did BANKNIFTY move, and did it cover the time lost?
Open these next: