Understanding Option Premium in Indian Markets

What an Option Premium Actually Is

Option premium is the price the buyer pays the seller for an option. A call gives the right to buy and a put the right to sell at the strike, the contract’s agreed price. Index options settle the difference in cash. On NSE, quoted premium is per unit; multiply it by the total units to find the position cost.

Illustrative example: a Nifty 24,500 call has premium ₹120 and assumed total quantity 65 units. Premium paid is 120 × 65 = ₹7,800, before charges. The quantity is an assumption rather than a current lot-size quotation. A short call can lose much more than its premium received.

An option premium cannot fall below zero. If an option expires worthless, its buyer loses the premium paid, plus costs. A low premium alone does not make a trade inexpensive in risk terms.

Option Premium Formula for Calls and Puts

The premium you see on screen is the market price, set by buyers and sellers. It can always be split into two parts, and that split is the formula people usually mean when they ask how option premium is calculated.

• Premium = intrinsic value + time value.
• Call intrinsic value = spot price minus strike price, or zero if that is negative.
• Put intrinsic value = strike price minus spot price, or zero if that is negative.
• Time value = premium minus intrinsic value. It cannot be set by formula alone; you read it from the market price.

Pricing models such as Black-Scholes estimate a theoretical premium from spot, strike, time left, implied volatility (the expected swings built into the price) and interest rates. The market price you actually pay can differ from that estimate. All numbers on this page are made-up examples, not live quotes.

The Two Components: Intrinsic Value and Time Value

Every premium splits cleanly into two parts. Intrinsic value is the in-the-money amount: for a call it is spot minus strike (floored at zero), and for a put it is strike minus spot (floored at zero). Time value, sometimes called extrinsic value, is whatever is left in the premium after intrinsic value. Time value is what you pay for the possibility that the option moves further into the money before expiry.

Suppose, in a made-up example, Nifty is at 24,650 and a 24,500 call trades at ₹210. Intrinsic value is ₹150 and time value ₹60. If the final settlement level is also 24,650, expiry value is ₹150 per unit. The difference from the assumed purchase premium is a ₹60 loss per unit before charges.

Out-of-the-money options have zero intrinsic value, so their premium is time value. That value can disappear at expiry. There is no fixed rate at which a particular premium must fall.

Premium for ITM, ATM and OTM Options

Moneyness describes where the strike sits against the spot price. An option is in the money (ITM) when it has intrinsic value, at the money (ATM) when the strike is at or very near spot, and out of the money (OTM) when it has none. See moneyness for more.

• ITM: premium is mostly intrinsic value. In the table above the 24,200 call is 300 of 360 intrinsic value.
• ATM: all the premium is time value, so it is the part most exposed when time passes or volatility falls.
• OTM: premium is time value only and is usually the lowest. It is low because the option needs a larger move to reach intrinsic value, not because it is safe: it can still go to zero.

Near-the-money strikes tend to carry the largest time value, and time value shrinks as the strike moves far in or out of the money. That is a general pattern, not a rule for every contract. The option chain shows each strike's premium side by side.

What Affects an Option Premium

Premiums depend on the underlying price, strike, time remaining, implied volatility and rates, with dividends or carrying costs also relevant. Greeks estimate sensitivity to each input near its current value, holding the others unchanged. Several inputs can change together.

• Underlying price: a call gains value as spot rises, a put gains value as spot falls. This sensitivity is measured by Delta.
• Strike price: deeper in-the-money strikes carry more intrinsic value and therefore higher premiums.
• Time to expiry: more remaining time generally adds time value, with exceptions depending on the contract and model. Theta estimates time sensitivity; it is not a fixed daily deduction.
• Volatility: higher implied volatility, the expected swings reflected in an option’s price, can raise call and put premiums when other inputs are unchanged. Vega measures that sensitivity.
• Interest rates: a smaller effect in practice, captured by Rho, more relevant for longer-dated contracts.

Implied volatility can rise before an event and fall afterward, but that pattern is not guaranteed. A fall in volatility or time value can outweigh a favourable move in the underlying.

A Fully Worked Bank Nifty Example with Charges

Made-up Bank Nifty monthly-call example: assume spot 51,800, strike 52,000, premium ₹240 and total quantity 30 units. The quantity is assumed, not a live lot-size claim.

• Example premium paid: 240 × 30 = ₹7,200, before charges.
• Assume the option later sells at ₹520 per unit; this exit premium is not inferred from a spot-price move.
• Example sale proceeds: 520 × 30 = ₹15,600.
• Gross profit: 15,600 − 7,200 = ₹8,400.

For this example sale, STT is 0.15% of ₹15,600 = ₹23.40 before statement rounding. This uses the rate effective 1 April 2026, checked 16 October 2026. Brokerage and other charges remain separate.

Profit less STT alone is ₹8,376.60. This is not net profit: deduct brokerage and all other applicable charges before comparing realised outcomes.

What One Lot of Premium Costs: Buyer and Seller Cash Flow

Yes, a buyer pays the premium up front. The seller receives it, but must also keep margin with the broker. Total premium is the price per unit times the units in the contract. NSE's lot file for Nov 2026 shows a Nifty 50 lot of 65 units, so it is used below; always check the file for your expiry.

The buyer's cash outflow is the whole premium plus charges, and that is the most a standalone long option can lose. The seller of the 24,500 call receives ₹9,750 but is not simply ₹9,750 better off. Margin is blocked on top, and the loss can be far larger if the market rises. The premium is not the seller's maximum profit guarantee either; it is the most they can keep, and only if the option expires worthless. See F&O margin requirements.

What the Option Greeks Measure

Option Greeks estimate how sensitive the premium is to individual pricing inputs. Delta concerns underlying-price changes, gamma changes in delta, theta elapsed time, vega implied volatility and rho interest rates. These estimates can change as the market moves.

A long option can lose value while the underlying moves in the expected direction. The size and speed of that move, volatility changes, time elapsed and execution costs all matter.

Calls Versus Puts: How Premiums Behave Differently

Calls and puts are mirror images in their reaction to the underlying, but they share the same drivers for time value and volatility. The table below summarises how each behaves so you can read an option chain at a glance.

NSE index options are cash settled. Stock-option expiry can create delivery obligations, so the standalone option’s premium-risk description should not be treated as a cap on any resulting stock exposure. NSE’s Nifty product page uses conflicting physical-settlement wording; NSE Clearing describes index exercise settlement in cash.

Weekly and Monthly Expiry Mechanics on NSE and BSE

As checked on 16 October 2026, NSE Nifty weekly options expire on Tuesday and monthly options on the last Tuesday, with the preceding trading day used for a holiday. Bank Nifty has monthly and quarterly options, without weekly contracts. Read the actual expiry date before comparing premiums.

Compare time remaining rather than assuming a product labelled weekly is always cheaper or faster-decaying. Strike, implied volatility and the underlying matter too. Selling a short-dated option exposes the writer to adverse price changes as well as time decay.

Why Premium Falls on Expiry Day

As expiry approaches, the chance of a big move shrinks, so the time value part of the premium shrinks with it. On expiry day only intrinsic value remains. An at-the-money option with ₹150 of time value in the morning can lose most of it by the close if spot stays near the strike, while an option that finishes out of the money is worth zero.

Time value usually shrinks faster close to expiry, but it is not a fixed rupee amount each day, and a jump in implied volatility can lift it again. This is why a long option can lose money on a day when the index moves your way slowly. Read more in theta decay and option Greeks.

Writing down premium per unit, units, entry time and the reason for the trade in your journal makes it easier to see later whether losses came from direction, from time passing or from paying too much for volatility. OneTradeJournal estimates charges for each trade you log by hand; it does not show live premiums.

Tax Records for Option Trading

An option premium is not the same as taxable profit. Preserve buys, sales, expiry settlements and charges, and have the applicable income-tax classification checked for your transactions.

Loss set-off, carry-forward and audit obligations depend on legal conditions and the relevant period. This premium guide does not establish eligibility for any deduction or loss relief.

• Retain contract notes and broker statements.
• Separate premium cash flows from realised profit and charges.
• Check sale STT and exercise STT separately.

Ask a qualified chartered accountant about your own tax position rather than applying delivery-equity rates to an option trade.

Margins, Lot Sizes and SEBI Guardrails

A long option normally requires its premium and costs up front. Writers require margin; the amount depends on the contract, position and current requirements. Margin is a deposit requirement, not the maximum possible loss.

The latest exchange contract file is the reference for the selected expiry’s quantity. Do not reuse an old index-lot table or infer a regulatory motive from a lot-size revision.

• Account for premium, costs and any expiry-related requirements for a long option.
• Check current margin for the entire short-option position.
• Multiply each premium point by total underlying units to understand rupee exposure.

Practical Ways to Read and Use Premiums

Compare the premium with the distance between the strike and the underlying price. Check the option’s implied volatility, meaning the expected swings reflected in its price, alongside time remaining. Record those observations separately from the actual entry, exit and charges.

A covered call pairs a stock holding with a short call and limits upside while retaining stock downside. A protective put adds downside protection at a premium cost. Neither label makes the position suitable for every trader; compare full-position outcomes and settlement needs.

For more detail, see expiry comparisons, STT bases and exercise and assignment.

Sources

• OIC: Options pricing (checked 16 Oct 2026)
• NSE: Bank Nifty specifications (checked 16 Oct 2026)
• NSE: Nifty expiry specifications (checked 16 Oct 2026)
• NSE: April STT revision (checked 16 Oct 2026)
• Zerodha: Option STT bases (checked 16 Oct 2026)
• OIC: Delta sensitivity (checked 16 Oct 2026)
• OIC: Gamma sensitivity (checked 16 Oct 2026)
• OIC: Theta sensitivity (checked 16 Oct 2026)
• OIC: Vega sensitivity (checked 16 Oct 2026)
• OIC: Rho sensitivity (checked 16 Oct 2026)
• NSE Clearing: Index exercise settlement (checked 16 Oct 2026)
• Zerodha: Index cash and stock delivery settlement (checked 16 Oct 2026)