Last updated 10 September 2026
Why an option basket leg shows a different price from the last traded price
- Nothing is wrong. The two numbers are different on purpose.
- The chain shows the last traded price — what somebody else got, earlier.
- Your basket shows what you will get now. All legs go at market, so the price comes from the market, not from history.
- A leg you are buying is priced at what sellers are asking. A leg you are selling is priced at what buyers are bidding.
- It is usually a little worse than the last traded price, and that is the honest figure — you can compare it with your own fills afterwards.
- The gap between the two prices is already included. The screen also tells you, in rupees, how much of the total it is.
When this happens
- 1 The leg is a buy, so it is priced at the price sellers are asking, which is above the last traded price.
- 2 The leg is a sell, so it is priced at the price buyers are bidding, which is below the last traded price.
- 3 The contract trades thinly, so the two prices are far apart and the difference from the last traded price is large.
- 4 The contract has not traded for a while, so its last traded price is old while its quotes are current.
You built an option basket on the Options screen, and the Price on a leg is not the same as the price shown for that strike in the chain above it.
Nothing has gone wrong. The two numbers answer two different questions.
Two prices, two meanings
A traded contract always has more than one price.
- The last traded price is what somebody else paid or received the last time that contract changed hands. It is history. On a strike that trades rarely it can be minutes old.
- The price buyers are bidding is the best price anyone is currently willing to buy at. If you sell right now, this is what you receive.
- The price sellers are asking is the best price anyone is currently willing to sell at. If you buy right now, this is what you pay.
The chain shows you the last traded price. Your basket shows you the other two, because those are the ones you will actually trade at.
Why the basket uses the buying and selling price
Every leg of a basket is sent as a market order. That is on purpose: a limit order can sit unfilled, and a half-filled structure does not behave like the structure you built.
Because the order goes at market, the price is already decided by the market, not by you:
| Your leg | It is priced at | Because |
|---|---|---|
| BUY | the price sellers are asking | that is who you will buy from |
| SELL | the price buyers are bidding | that is who you will sell to |
So a buy leg usually shows a slightly higher price than the last traded price, and a sell leg a slightly lower one. That is not the screen being pessimistic. It is the screen being honest, so the net debit or credit it shows you is a figure you can compare with your own fills afterwards.
Why the middle price is the fair one, and not the last traded price
It is natural to treat the last traded price as the real value, and then to feel that anything above it is a charge. But the last traded price is not a neutral number.
Almost every trade happens at one of the two quoted prices. So the last traded price is always one side of the market, frozen at the moment somebody traded:
- If the last trade was a sell, it went at the bidding price.
- If the last trade was a buy, it went at the asking price.
Now picture a contract quoted at 100 and 102 all day, with neither price ever moving. Trades come in: a sell, then a buy, then a sell.
| The last trade was | The last traded price reads | Buying at 102 looks like it costs extra |
|---|---|---|
| a sell | 100 | 2 |
| a buy | 102 | 0 |
| a sell | 100 | 2 |
Nothing changed in the market. Your purchase costs you the same amount every time. Only the number you were comparing it against moved, because that number is really just a record of who traded last.
The middle price does not jump about like that. It stays at 101 all day, so the cost of buying is a steady 1 every time. That is why the screen measures against the middle price.
For the full working, see how the spread figure is worked out.
Where the difference goes
The distance between the two prices is a real cost, and it is already inside every figure on your basket — each leg’s Price, each leg’s Value, and the net debit or credit at the bottom.
You are not charged it twice. The screen shows it separately only so you know how large it is: a line under the leg table gives it in rupees. On a heavily traded strike it is small. On one almost nobody trades it can be larger than the premium itself, and the leg then also carries a tag — wide, very wide, not traded or no quote. See what those tags mean.
When only one price is available
Some contracts are quoted on one side only — there are buyers but no sellers, or the other way round. There is then no price to trade at on the missing side, so that leg falls back to its last traded price and carries the no quote tag.
Treat that leg’s figure with more care than the others: it is the only kind of leg where the price shown is not a price you can be sure of getting.
What to do
Nothing. The basket is working as intended.
If you want to see the two prices for yourself, they are in the chain: each side of every strike shows the price buyers are bidding and the price sellers are asking, beside the last traded price. Compare them with the Price on your leg and you will see where the number came from.
The Options screen is in beta. Whatever it shows you before you place, always check your order book at your broker afterwards to confirm what actually happened.
