An option is a contract that gives its buyer the right, but not the duty, to buy (a call) or sell (a put) something at a fixed price, the strike, until a fixed date, the expiry. In India that "something" is either an index, such as NIFTY 50, NIFTY Bank or SENSEX, or a single stock, such as Reliance Industries or HDFC Bank. Both are traded in the futures and options (F&O) segment of NSE and BSE, both use the same option chain layout, and both are priced by the same forces. But they behave very differently once you hold them.
This guide explains the five differences that matter most: what you get at expiry, how easy it is to trade, how many expiries there are, how much a single piece of news can move the price, and how margins work.
Difference 1: cash settlement vs delivery
An index cannot be delivered: nobody can hand you "one NIFTY". So index options are cash settled. If you hold a NIFTY 25,000 call at expiry and NIFTY settles at 25,180, the exchange simply credits you the difference, 180 points multiplied by the lot size. If the option ends out of the money, it expires worthless and nothing else happens.
Stock options in India are physically settled. If a stock option is in the money at expiry, the buyer and the seller must actually exchange shares. A call buyer has to pay for the full value of the shares and receives them in their demat account; a put buyer has to hand over shares. That can mean needing lakhs of rupees, or shares you do not own, on expiry day. It is the single biggest practical difference and has its own guide: physical settlement of stock options.
Because of this, most stock option traders close their positions a few days before expiry, and many brokers close them on their own if the client does not.
Difference 2: liquidity and the cost of trading
Liquidity means how easily you can buy or sell without moving the price. Index options are among the most traded contracts in the world. Near the current price, NIFTY options trade many thousands of times a minute and the gap between the best buy price and the best sell price (the bid-ask spread) is often a single tick of ₹0.05.
Here is part of today's NIFTY option chain. Each row is a strike; calls are on the left and puts on the right, with open interest showing how many contracts are still open:
Notice how many strikes on either side of the highlighted at-the-money row carry large open interest. In most stock option chains only a handful of strikes near the price trade actively, and strikes further away can go a whole session without a trade. A wide spread there costs you money every time you enter and exit, which is explained in the bid-ask spread guide.
Difference 3: expiries
Index options come in weekly and monthly expiries. After the market regulator SEBI's changes in late 2024, each exchange keeps a weekly expiry on one main index (NIFTY on NSE, SENSEX on BSE), while other indices such as BANKNIFTY have monthly expiries. Stock options have only monthly expiries, usually the current month, the next month and the month after.
Expiry days and the list of indices with weekly contracts have changed several times, so check the current calendar on NSE and BSE or on the expiry page before you plan a trade. The expiry guide covers how weekly and monthly contracts differ in price and decay.
Difference 4: event risk and how far prices can jump
An index is an average of many companies. When one bank reports weak results, the others may not, so the index moves less than its members. A single stock has no such cushion. Quarterly results, a court order, a management change, a block deal or a broker downgrade can move one share 5-10% in minutes. The options market knows this, so stock options usually carry a higher implied volatility (the amount of movement priced in) than index options.
A stock's technical picture shows how wild its daily swings already are. Here is the live technical summary for Reliance Industries:
Look at how far the stock sits from its moving averages and how stretched its momentum readings are. A stock far from its averages, or with results due soon, can gap sharply, and its options will price that in. The site's results moves page compares the move each stock's options expected around results with what actually happened.
Difference 5: lot sizes, margins and position limits
Every F&O contract trades in fixed lots. The exchange sets lot sizes so that one lot is worth a minimum contract value, and revises them from time to time, so a NIFTY lot and a Reliance Industries lot will be worth roughly similar amounts but contain very different numbers of units. Check the current lot size on NSE or with your broker before trading.
Option buyers pay only the premium. Option sellers must keep a margin, which is usually higher as a share of contract value for stocks than for indices, because single stocks are more volatile. Stock options also have a market-wide position limit: when open positions in a stock's derivatives cross a set share of the limit, the stock enters the F&O ban and traders can only reduce positions, not add new ones, until it falls back. Indices have no such ban.
Side by side
| Point | Index options | Stock options |
|---|---|---|
| Settlement | Cash | Delivery of shares if in the money |
| Exercise style | European (at expiry) | European (at expiry) |
| Expiries | Weekly on the main index, monthly on others | Monthly only |
| Liquidity | Very deep near the money | Good in large stocks, thin in many |
| Bid-ask spread | Often one tick | Often several ticks, wider away from the money |
| Event risk | Budget, RBI policy, global shocks | All of those plus results and company news |
| F&O ban | No | Yes, when open positions cross the limit |
How traders use each one
- Index options are used to trade the overall market, to hedge a portfolio of shares (buying NIFTY puts, explained in the portfolio hedging guide), and for intraday strategies such as the short straddle, where tight spreads matter.
- Stock options are used to trade a view on one company, especially around results, to earn income on shares already owned (a covered call), or to protect a single holding (a protective put).
- Some traders compare the two directly: if a stock's options price a 7% move for results while the index prices 2% for the month, the gap shows how much of the risk is company-specific.
Common mistakes
- Holding an in-the-money stock option into expiry by accident. You may be forced to buy or deliver shares worth many times the premium.
- Using market orders in thin stock options. A market order can fill far from the last traded price. Use limit orders.
- Assuming a stock option behaves like a NIFTY option. The same strategy with the same rules can carry very different risk because of gaps on results days.
- Forgetting the F&O ban. A position in a banned stock cannot be increased, and adjustments become harder.