Ask Price
The lowest price a seller will accept — the price you pay when you buy an option at market.
Definition
The ask price (also called the offer price) is the minimum price at which the best available seller in the market is willing to part with an option contract right now. Whenever you submit a market buy order — or a limit buy order priced at or above the ask — your order executes at the ask. The ask is always higher than the bid price, and the gap between them is the bid-ask spread, which is an implicit cost you absorb on every entry.
Why it matters
On NSE's electronic limit-order book, the ask you see in the option chain is the best (lowest) outstanding sell order across all market participants. In highly liquid contracts — ATM Nifty or Bank Nifty weekly options — the ask can be just ₹0.05 above the bid, meaning your entry slippage is minimal. But for deep OTM strikes or options on less-traded stocks, the ask can sit ₹1–₹5 or more above the last traded price, making market orders expensive.
Because options are priced per unit and each lot on Nifty is 75 units, a ₹1 wider ask costs you ₹75 extra per lot. Multiply that across multiple lots and the ask-relative-to-mid-price matters as much as the strategy itself. Professional traders almost always use limit orders priced near the mid-point — halfway between bid and ask — and adjust from there rather than paying the full ask outright.
The ask also shifts dynamically as the underlying moves. In a fast-rising market, option sellers widen their asks rapidly to protect themselves from being lifted at stale prices. This is why options can appear to "jump" in price even when the underlying has moved only modestly — sellers are repricing their asks in real time.
How it works
The ask is determined by the order book: the lowest-priced sell limit order currently resting in the system becomes the best ask. If that order gets filled (someone buys it), the next-lowest sell order becomes the new best ask. In fast markets, the ask can move tick by tick in under a second. On NSE, the minimum tick size for most equity options is ₹0.05, so the ask advances in ₹0.05 increments.
Example
Suppose Nifty is trading near 24,000 and the 24,000 CE weekly expiry shows a bid of ₹120 and an ask of ₹121. If you hit "buy at market," your order fills at ₹121 per unit. With a lot size of 75, your actual outlay is ₹9,075 — not ₹9,000 at the mid. If instead you place a limit order at ₹120.50 (the mid), you might get filled within a few seconds if a seller accepts; if not, you can inch the limit up. The ₹0.50 saving per unit across 2 lots saves ₹75 — roughly the cost of brokerage on many platforms.
See live asks on every strike
TradePulse's option chain shows real-time bid and ask for every Nifty and Bank Nifty strike.