Options Trading: Call, Put, Strike, Premium Explained

What Is an Option Contract? The Building Blocks

An option is a type of derivative - meaning its value is derived from an underlying asset rather than having intrinsic value of its own. In the Indian market, the underlying asset can be an equity index (like Nifty 50 or Nifty Bank), an individual stock listed on NSE or BSE, a currency pair (traded on NSE's currency segment), or a commodity (on exchanges like MCX or NCDEX).

Every option contract has four fundamental components that you must understand before placing a single trade.

First is the underlying asset. This is what the option is written on - for example, Nifty 50 or a particular large-cap stock. When an index option is exercised, settlement is in cash because you cannot physically deliver an index. Stock options, on the other hand, are settled by delivery of shares in the Indian market.

Second is the type - call or put. A call option gives the buyer the right to purchase the underlying asset. A put option gives the buyer the right to sell the underlying asset. These two types are the bedrock of all options strategies.

Third is the strike price (also called the exercise price). This is the price at which the buyer can buy (for a call) or sell (for a put) the underlying when exercising the option. On NSE, multiple strike prices are listed for any given expiry - they are spaced at regular intervals above and below the current market price of the underlying.

Fourth is the expiry date. Indian equity options typically expire on the last Thursday of the contract month (or the previous business day if Thursday is a holiday). NSE introduced weekly expiries for index options - Nifty 50 options expire every Thursday, while various other index options have their own weekly schedules. This has dramatically increased trading activity since traders can take short-term views without waiting for a monthly expiry.

There is also an important distinction between option styles. European-style options can only be exercised on the expiry date itself, not before. American-style options can be exercised at any time before expiry. In India, all index options (including Nifty 50 and Nifty Bank) are European-style. Individual stock options on NSE are also European-style following a regulatory change by SEBI. This matters because you cannot exercise an in-the-money option early; instead, you simply sell it in the market before expiry if you want to realise your profit.

Each option contract represents a standard lot size - the minimum number of units of the underlying per contract. Lot sizes are set by SEBI and the exchanges, and they change periodically to keep the notional contract value within a specified range. Always check the current lot size on NSE before trading, as these can be revised.

Call Options: The Right to Buy

A call option gives the buyer the right - not the obligation - to purchase the underlying asset at the strike price on or before the expiry date. In return for this right, the buyer pays a premium to the seller (also called the writer) of the call option.

When would you buy a call option? When you are bullish on the underlying asset - that is, when you believe the price will rise. If your view is correct and the underlying climbs above the strike price, your call option becomes profitable. Specifically, the option has intrinsic value equal to (Current Market Price − Strike Price). You can either sell the option in the market to capture the profit, or, for stock options, exercise it and receive the shares at the strike price.

If the price of the underlying stays below the strike price at expiry, the call expires worthless. The buyer loses the entire premium paid - but nothing more. This is the key asymmetry of options: the buyer's maximum loss is limited to the premium, while the potential profit can be theoretically unlimited as the underlying rises.

The seller (writer) of a call option has the mirror-image payoff. The seller collects the premium upfront. If the option expires worthless, the seller keeps the full premium as profit. However, if the underlying rises sharply above the strike price, the seller faces potentially unlimited losses because they are obliged to sell the underlying at the strike price regardless of how high the market has gone. This is why selling naked call options is considered very high risk and requires significant margin deposits with the broker.

In the Indian market, call buying is one of the most popular strategies, particularly around events like quarterly earnings announcements, Union Budget day, RBI Monetary Policy Committee meetings, and global macroeconomic events. Traders buy Nifty 50 calls when they expect the market to surge, or buy calls on individual stocks before expected positive news.

It is worth noting that most retail options traders in India do not hold positions to expiry. They buy and sell options intraday or over a few days, attempting to profit from changes in the option's price (premium) rather than from actual exercise. This makes options very much a trading instrument as much as a hedging tool.

A covered call is a popular strategy where an investor who already holds shares sells call options on those shares to earn premium income. For example, if you own shares in a company and the stock has been range-bound, you might sell a call at a strike above the current price. If the stock stays flat or falls slightly, you keep the premium. If it rises above the strike, your shares are called away at the strike price, but the premium provides a cushion. Covered calls are discussed more fully in the related article on covered calls.

Put Options: The Right to Sell

A put option gives the buyer the right - not the obligation - to sell the underlying asset at the strike price on or before the expiry date. The buyer pays a premium to the seller for this right.

You would buy a put option when you are bearish on the underlying - when you expect the price to fall. If the underlying declines below the strike price, the put becomes profitable. The intrinsic value is (Strike Price − Current Market Price). As with calls, you can sell the option in the market before expiry to book profits without actually delivering shares.

If the underlying stays above the strike at expiry, the put expires worthless and the buyer loses only the premium. The buyer's maximum loss is always limited to the premium paid. The maximum gain, theoretically, is capped at (Strike Price − Zero), since the underlying's price cannot go below zero - but in practice, a large fall in the underlying can make a put very valuable.

Put options serve a vital hedging function. Portfolio managers and large investors routinely buy put options on indices or individual stocks to protect their portfolios. This is sometimes called a protective put. If you hold a large portfolio of Nifty 50 constituent stocks and you fear a market correction, buying Nifty put options can offset portfolio losses. If the market falls, your puts gain in value, compensating for some of the paper losses on your equity holdings. Think of it as portfolio insurance - you pay a premium (the cost of the puts) for downside protection.

The seller (writer) of a put option collects the premium and is obligated to buy the underlying at the strike price if the buyer exercises. If you sell a put, you are effectively saying: "I am willing to buy this stock or index at the strike price." If the underlying falls sharply, the put seller suffers losses because they must buy at the (now higher) strike price in a falling market. Naked put selling therefore requires substantial margin.

A cash-secured put is a more conservative strategy where an investor sells a put on a stock they would genuinely like to own at a lower price. If the put is exercised, they acquire the shares at the strike price, but having already received the premium, their effective cost is (Strike Price − Premium). If the stock stays above the strike, they simply keep the premium.

In the Indian context, put buying surges during periods of geopolitical tension, poor global cues, or domestic economic uncertainty. During sharp market corrections, Nifty put options can multiply several times in value over a matter of hours, making headlines and drawing many speculative traders. However, such situations also illustrate the time decay risk - a put bought too early can lose value steadily before the anticipated fall materialises.

Strike Price and Moneyness: In-the-Money, At-the-Money, Out-of-the-Money

The strike price - also called the exercise price - is the fixed price at which the option buyer can buy (call) or sell (put) the underlying. It is one of the most critical parameters of any option, determining whether an option has intrinsic value at any given moment.

The relationship between the current market price of the underlying and the strike price gives rise to the concept of moneyness, which classifies every option into one of three categories: in-the-money (ITM), at-the-money (ATM), or out-of-the-money (OTM).

A call option is in-the-money when the current price of the underlying is above the strike price. For example, if Nifty 50 is trading at 22,500 and you hold a call with a strike of 22,000, that call is in-the-money by 500 points. It has intrinsic value of 500. An ITM call is more expensive because it already has real, realisable value.

A call option is out-of-the-money when the current price is below the strike price. A 23,000 call when Nifty is at 22,500 is OTM by 500 points. It has zero intrinsic value; its entire premium consists of time value. OTM options are cheaper but have a lower probability of expiring in-the-money.

A call is at-the-money when the strike price equals (or is very close to) the current market price. ATM options typically have the highest time value because there is the most uncertainty about which direction the final outcome will go.

For put options, the logic is reversed. A put is in-the-money when the current price is below the strike (e.g., a 22,000 put with Nifty at 21,500 is ITM). A put is out-of-the-money when the current price is above the strike. A put is at-the-money when prices are roughly equal.

Moneyness is critically important for several reasons. It tells you the probability of profit at expiry (OTM options have a lower probability of finishing in-the-money), the option's sensitivity to price movements in the underlying (ITM options move more in line with the underlying), and the composition of the premium between intrinsic value and time value.

On NSE, when you open the options chain for any underlying, you will see a matrix of strike prices arranged in rows, with call option prices on one side and put option prices on the other. The ATM strike is usually highlighted or easily identifiable as the one closest to the current price. Strikes above the ATM are OTM calls and ITM puts; strikes below the ATM are ITM calls and OTM puts.

There is also the concept of deep ITM versus deep OTM. Deep ITM options behave almost like holding the underlying itself, with very little time value. Deep OTM options are very cheap but have a very low probability of ever moving into profitable territory. Many retail traders are drawn to deep OTM options because of their low absolute cost, but they frequently expire worthless - a pattern worth taking seriously.

Option Premium: What You Are Really Paying For

The premium is the price you pay (as a buyer) or receive (as a seller) for an option. It is quoted per unit of the underlying, and the total cost of a contract is (Premium × Lot Size). Understanding what drives the premium is essential because it determines whether a trade is fairly priced and what factors will influence its value over time.

Option premium has two components: intrinsic value and time value (also called extrinsic value).

Intrinsic value is the immediate, realisable value of the option if it were exercised right now. For a call, intrinsic value = max(0, Current Price − Strike Price). For a put, intrinsic value = max(0, Strike Price − Current Price). An OTM option has zero intrinsic value; an ITM option's intrinsic value increases as it moves further in-the-money.

Time value is everything else - the portion of the premium beyond the intrinsic value. Time value reflects the possibility that the option will become more profitable before expiry. Several factors drive time value:

Time to expiry is one of the most powerful drivers. The more time remaining, the higher the time value, because there is more opportunity for the underlying to move favourably. As expiry approaches, time value erodes - a phenomenon called time decay, measured by the Greek letter Theta. This erosion accelerates dramatically in the final week before expiry. For buyers, time decay is the enemy; for sellers, it is their friend.

Implied volatility (IV) is the market's consensus estimate of how much the underlying will move over the remaining life of the option. Higher implied volatility means a higher premium because the underlying is expected to make larger moves, increasing the probability of the option finishing in-the-money. IV is not directly observable but is derived from actual market prices of options. When market uncertainty spikes - before a major event or during a crisis - IV rises sharply, inflating premiums. After the event passes, IV often collapses, causing option premiums to fall even if the underlying moves in the expected direction. This is called a volatility crush and is one of the most unpleasant surprises for inexperienced options buyers.

Interest rates and dividends also influence premiums, though these effects are more subtle for retail traders. The risk-free interest rate (often approximated by the RBI's repo rate or short-term government bond yields in India) affects the cost of carrying positions. Dividends expected before the expiry date reduce call premiums and increase put premiums for stock options, because a dividend payment reduces the stock price on the ex-date.

The mathematical model most widely used to price options is the Black-Scholes model. While you do not need to use this model manually, understanding its inputs helps you appreciate why option prices move the way they do. The Black-Scholes inputs are: the current price of the underlying, the strike price, the time to expiry, the risk-free interest rate, and the implied volatility. Of these, implied volatility is the only one that is not directly observed - it is backed out from the market price of the option itself. The NSE publishes the India VIX, an index that measures the implied volatility of Nifty 50 options over the next 30 days. A rising India VIX signals increased fear and uncertainty; a falling India VIX signals calm. Traders watch India VIX closely as it directly affects option premiums.

Option Greeks: Measuring Sensitivity

Options pricing is not static. As the underlying price, time, or volatility changes, the premium moves - but not always in straightforward ways. The Option Greeks are a set of measures that quantify how sensitive an option's price is to various factors. They are named after Greek letters and are used by traders to understand and manage risk. A foundational understanding of the major Greeks is essential for anyone trading options beyond the most basic level.

Delta is the most important Greek for most traders. It measures how much the option's premium changes for a one-unit (one rupee or one point) change in the underlying's price. A Delta of 0.5 means that if the underlying rises by ₹1, the option premium rises by approximately ₹0.50. Call options have positive Delta (ranging from 0 to 1); put options have negative Delta (ranging from −1 to 0). An ATM option typically has a Delta close to 0.5. Deep ITM options have a Delta close to 1 (for calls) or −1 (for puts); deep OTM options have a Delta close to zero. Delta is also commonly interpreted as the approximate probability that the option will expire in-the-money.

Gamma measures the rate of change of Delta itself. It tells you how quickly Delta will change as the underlying moves. High Gamma means Delta changes rapidly, making the option's behaviour harder to predict. Gamma is highest for ATM options near expiry, which is why weekly expiry options on Nifty can have extremely sharp price swings in the final hours of trading.

Theta represents time decay - the amount by which the option's premium decreases each day, all else being equal. Theta is always negative for option buyers (their premium erodes each day) and positive for option sellers (they benefit from time passing). ATM options close to expiry have the highest Theta - they lose value the fastest in absolute terms. Weekly expiry options have extremely high Theta, which is why many traders focus on selling weekly options to harvest this time decay.

Vega measures the sensitivity of the option premium to a one-percentage-point change in implied volatility. A Vega of 10 means that if IV rises by 1%, the option premium increases by ₹10 per unit. Both calls and puts have positive Vega - higher IV increases the value of both. Option buyers benefit from rising IV; option sellers suffer. This is why buying options just before a major event (when IV is already elevated) can be risky - if IV falls after the event, option premiums can collapse even if the underlying moves in your favour.

Rho measures sensitivity to changes in the risk-free interest rate. For most retail traders in India, Rho is a minor consideration since interest rates typically change slowly and in small increments.

Understanding the Greeks allows traders to build strategies with specific risk profiles. For example, a trader who wants to be neutral on direction but profit from a rise in volatility might buy a straddle (buying both a call and a put at the same strike) - this position has near-zero Delta but positive Vega. A market maker or professional seller might construct a Delta-neutral portfolio to hedge directional risk while earning Theta.

For beginners, the practical takeaway is simple: if you buy options, time is working against you (Theta), volatility drops after events will hurt you (Vega), and you need the underlying to move significantly in your favour, quickly enough to overcome these headwinds.

How Options Are Traded on Indian Exchanges: NSE, BSE, and the Mechanics

In India, equity and index options are primarily traded on NSE (National Stock Exchange), with BSE also offering equity derivatives. Currency options are available on NSE's currency segment and BSE. Commodity options are available on MCX (Multi Commodity Exchange) for commodities like gold, silver, crude oil, and copper, and on NCDEX for agri-commodities.

To trade options, you need a trading account and a demat account with a SEBI-registered stockbroker. When you place an options order, you specify: the underlying, the option type (call or put), the strike price, the expiry date, the number of lots, the order type (market or limit), and whether you are buying or selling.

Options are traded in a continuous, order-driven market during NSE's trading hours (currently 9:15 AM to 3:30 PM IST for equity derivatives). For currency derivatives, trading hours extend into the evening. Commodity options on MCX trade until 11:30 PM IST on most nights. Prices are determined by supply and demand, reflected in the bid-ask spread for each option contract.

Lot size is a crucial concept. Each options contract covers a specified number of units. For Nifty 50 options, the lot size is 25 (as of recent periods, though SEBI revises this). This means one Nifty 50 options contract controls 25 units of the index. If a Nifty call is trading at a premium of ₹200, the cost of one contract is ₹200 × 25 = ₹5,000. Always verify the current lot size on NSE's website before trading.

Margin requirements differ substantially between buyers and sellers. Option buyers pay the full premium upfront and have no further margin obligation - their maximum loss is defined. Option sellers, however, must deposit margin with their broker because their potential losses can be very large. SEBI mandates a specific margin framework (SPAN + Exposure margin) for derivatives. Margins for short option positions can be several times the premium received, reflecting the risk of adverse moves.

Expiry and settlement mechanics are important to understand. In the Indian market, index options are cash-settled - on expiry, NSE calculates the settlement price (typically the final closing value of the index on expiry day) and credits or debits the profit or loss directly to your trading account. Stock options (and stock futures) are physically settled - meaning actual shares change hands if you have an ITM position at expiry. This change from cash settlement to physical settlement for stock derivatives was introduced by SEBI to reduce manipulation.

For most retail traders, the practical implication of physical settlement is that they should not hold deep ITM stock option positions into expiry unless they are prepared for actual share delivery. Most traders close their positions (square off by selling what they bought, or buying back what they sold) before the last few days of the expiry cycle to avoid settlement complications.

Brokerage and transaction costs are also relevant. NSE and BSE charge a transaction levy on options. SEBI charges a small regulatory fee. The Securities Transaction Tax (STT) applies differently to option buyers (on premium) and to exercised options (on the notional value at expiry, for ITM options). GST is charged on brokerage and exchange fees. These costs can significantly impact net profitability, especially for high-frequency options traders. Always refer to your broker's brokerage schedule and the latest Finance Act for current tax rates.

Popular Options Strategies: From Simple to Advanced

One of the great attractions of options is the ability to construct strategies with very specific risk and reward profiles - something impossible with plain stocks or futures. Below is an overview of the most commonly used strategies, progressing from simple to more complex.

Buying a Call (Long Call): The most basic bullish strategy. You pay a premium for the right to buy the underlying at the strike price. Maximum loss is the premium; maximum gain is unlimited. Best suited when you have a strong bullish view and want defined risk.

Buying a Put (Long Put): The most basic bearish strategy. You pay a premium for the right to sell at the strike price. Maximum loss is the premium; maximum gain is limited only by how far the underlying can fall. Used for speculation on price declines or to hedge a long portfolio.

Covered Call: You own the underlying shares and sell a call against them. This generates premium income but caps your upside if the stock rises sharply above the strike. Popular among long-term investors who want to enhance returns on a range-bound portfolio.

Protective Put: You own shares and buy a put to protect against a price decline. This is essentially portfolio insurance. The put acts as a floor - if the stock falls below the strike, your put gains in value, limiting losses.

Bull Call Spread: You buy a call at a lower strike and simultaneously sell a call at a higher strike. The premium received from selling the higher strike partially offsets the cost of buying the lower strike. This reduces your maximum profit but also lowers your upfront cost and break-even. A good strategy when you are moderately bullish.

Bear Put Spread: You buy a put at a higher strike and sell a put at a lower strike. This reduces the net cost of the bearish position but also caps the maximum profit. Suitable for a moderately bearish view.

Long Straddle: You buy both a call and a put at the same strike price and expiry. This profits if the underlying makes a large move in either direction. The risk is that if the underlying stays near the strike, both options lose time value and you lose the combined premium. Often used ahead of major events like RBI policy announcements, Budget, or election results when the direction is uncertain but a big move is expected.

Long Strangle: Similar to a straddle, but you buy an OTM call and an OTM put. It is cheaper than a straddle but requires an even larger move to be profitable.

Iron Condor: A more advanced strategy where you sell an OTM call, buy a further OTM call, sell an OTM put, and buy a further OTM put. The result is a range-bound strategy that profits if the underlying stays within a specific range until expiry. Maximum profit is the net premium received; maximum loss is limited. Popular among experienced traders who believe the market will remain relatively stable.

Calendar Spread: You buy an option for a later expiry and sell the same strike option for a nearer expiry. This exploits the faster time decay of the near-term option. Profitable in stable markets.

Each of these strategies has its own break-even calculations, risk/reward profile, and ideal market conditions. As strategies grow in complexity, managing them requires a solid understanding of the Greeks. Beginners are strongly advised to start with simple long calls or long puts and thoroughly paper-trade before using real capital on multi-leg strategies.

Options for Hedging: Protecting Your Portfolio

While options are often associated with speculation, their original and most fundamental purpose is hedging - reducing risk. For investors holding significant equity portfolios, options provide a powerful and flexible tool to manage downside exposure.

Consider a long-term investor with a large portfolio of equity stocks that largely mirrors the Nifty 50 composition. This investor is comfortable holding stocks for the long term but is worried about a potential 10-15% market correction in the near term due to, say, global recession fears or domestic political uncertainty. Selling the entire portfolio would trigger tax events and transaction costs, and re-entering later brings its own risks.

Instead, this investor can buy Nifty 50 put options at a strike close to the current index level for the relevant expiry. If the market falls sharply, the puts gain in value, partially or fully offsetting the portfolio losses. If the market instead rises or stays flat, the puts expire worthless - but the investor still benefits from the portfolio appreciation. The cost of the puts (the premium paid) is essentially the insurance cost.

Hedging with options requires estimating the appropriate number of put contracts - a concept related to the portfolio's Delta relative to the index. This is sometimes referred to as calculating the hedge ratio. For a portfolio whose moves closely track Nifty, the number of Nifty puts needed is approximately: (Portfolio Value ÷ (Index Level × Lot Size)). In practice, this calculation should also account for the Delta of the specific put option chosen.

Corporate treasuries and institutional investors also use options to hedge currency risk. An Indian exporter expecting to receive USD in three months might buy USD put / INR call options on NSE's currency segment to lock in a minimum exchange rate. If the rupee strengthens (USD weakens), the put option compensates for the lower realised export value.

Hedging is not free. The premium paid is a real cost. Sophisticated investors often weigh the cost of the hedge against their risk tolerance and the probability of the adverse event occurring. Sometimes, they use strategies like collars (selling an OTM call to fund the purchase of an OTM put) to reduce or eliminate the net cost of hedging, accepting a cap on the upside in exchange for downside protection.

SEBI has encouraged the use of derivatives for hedging purposes and has established specific frameworks for institutional participants. Retail investors too can use index options for portfolio protection, and understanding this application helps demystify options beyond purely speculative use. However, executing a proper hedging strategy requires a clear understanding of your portfolio's composition, the relevant Greeks, and ongoing monitoring - it is not a set-and-forget approach.

Example

Key benefits

How it works

1. 1
   Open a Derivatives-Enabled Trading Account

   To trade options in India, you need a trading account with a SEBI-registered broker that is enabled for Futures and Options (F&O) trading on NSE or BSE. Your account must be linked to a demat account and a bank account for fund settlement.

2. 2
   Select the Underlying, Type, Strike, and Expiry

   Decide which underlying you want to trade (e.g., Nifty 50 index, a stock), whether you want a call or put, which strike price reflects your view, and which expiry date aligns with your time horizon. All available combinations are visible in the option chain on NSE or your broker's platform.

3. 3
   Check Premium, Open Interest, and Liquidity

   Before placing your order, review the current premium (price), the bid-ask spread, and the open interest for your chosen strike. High open interest and narrow spreads indicate a liquid contract - easier to enter and exit at a fair price.

4. 4
   Place Your Order and Pay Premium (for Buyers)

   Enter your order specifying the number of lots. For option buyers, the full premium × lot size is debited from your account upfront. For option sellers, a margin amount (calculated using SPAN + Exposure margin) is blocked in your account as collateral.

5. 5
   Monitor the Position and Manage Risk

   Once the position is live, monitor the premium, the underlying price, and the key Greeks (especially Delta and Theta). Have a pre-defined exit plan - either a target premium level at which you will book profit, or a stop-loss level to limit losses.

6. 6
   Square Off or Hold to Expiry

   Most traders close (square off) their positions before expiry by placing an opposite order - selling a call they had bought, or buying back a put they had sold. If you hold an ITM option to expiry, index options are cash-settled automatically; for stock options, be mindful of physical settlement obligations.

7. 7
   Account for Taxes and Transaction Costs

   After the trade, account for Securities Transaction Tax, brokerage, exchange transaction charges, and GST. Options profits are typically treated as business income under Indian tax law for active traders. Consult a tax advisor and refer to the latest Finance Act for applicable rates.

Formula

Option Premium = Intrinsic Value + Time Value
Intrinsic Value (Call) = max(0, Current Price − Strike Price) | Intrinsic Value (Put) = max(0, Strike Price − Current Price)

Key takeaways

Frequently asked questions

Related terms