What Is a Strike Price in Options? NIFTY and SENSEX Explained
Learn what an option strike price means, how strike selection affects Calls and Puts, ITM, ATM and OTM options, and why strike distance matters for NIFTY and SENSEX.
What Is a Strike Price?
The strike price is one of the most important concepts in options trading. It is the predetermined price at which the buyer of an option has the right to buy or sell the underlying asset, depending on whether the option is a Call or a Put.
For a Call Option, the strike price is the price at which the buyer has the right to buy the underlying. For a Put Option, it is the price at which the buyer has the right to sell the underlying.
Strike prices are therefore central to understanding option premiums, intrinsic value, moneyness, and potential payoff.
Strike Price in a Call Option
A Call generally benefits when the underlying moves above its strike price.
Suppose NIFTY is trading at 25,000 and you are analysing a 24,900 Call. Because the underlying is above the strike, the Call is in-the-money.
If NIFTY is instead at 24,700, the same 24,900 Call is out-of-the-money.
The strike itself has not changed. The option's moneyness changes because the underlying price has moved.
Strike Price in a Put Option
A Put generally benefits when the underlying moves below its strike price.
Suppose SENSEX is at 82,000 and you are analysing an 82,500 Put. The Put is in-the-money because the strike is above the current SENSEX level.
If SENSEX rises to 83,000, that same 82,500 Put becomes out-of-the-money.
Again, the strike price remains fixed while the underlying market price changes.
ITM, ATM and OTM Strike Prices
Strike prices are commonly described using three terms.
In-the-Money (ITM)
A Call is ITM when the underlying price is above the strike. A Put is ITM when the underlying price is below the strike.
ITM options have intrinsic value.
At-the-Money (ATM)
An ATM strike is generally the strike closest to the current underlying price. For example, if NIFTY is trading near a listed strike, that strike may be considered ATM depending on the available strike intervals.
ATM options often attract significant trading activity and can be important when analysing an option chain.
Out-of-the-Money (OTM)
A Call is OTM when its strike is above the underlying price. A Put is OTM when its strike is below the underlying price.
OTM options have no intrinsic value, although they can still have a market premium because there is a possibility that the underlying could move favourably before expiry.
Why Does Strike Selection Matter?
Choosing a strike is not simply a question of predicting whether the market will go up or down. The distance between the underlying price and the strike affects the option's premium, probability of finishing ITM, sensitivity to price changes, and risk profile.
For example, buying a far OTM NIFTY Call can appear inexpensive because its premium is small. However, NIFTY may need to make a large move before expiry for that option to develop substantial intrinsic value.
A cheaper option is therefore not necessarily a lower-risk option.
Strike Price and Option Premium
Option premiums generally vary across different strikes. If NIFTY is at 25,000, the 25,000 Call, 25,500 Call, and 26,000 Call will normally trade at different premiums.
The difference is influenced by moneyness, time to expiry, implied volatility, interest rates, and other pricing factors.
Near expiry, small changes in the underlying can produce significant changes in the value of options near important strikes.
Strike Selection for NIFTY and SENSEX
When analysing NIFTY or SENSEX options, traders often begin by identifying the current spot level and then examining nearby strikes.
A simple framework is:
This approach can help traders understand the option chain before deciding whether a particular strike fits their strategy.
Strike Price and Expiry
The same strike can behave very differently depending on the time remaining until expiry. A 25,000 Call with several weeks remaining has more time for NIFTY to move than a 25,000 Call expiring today.
As expiry approaches, time value generally declines and the option's behaviour becomes increasingly influenced by the relationship between the underlying price and strike price.
Strike Price Does Not Predict the Market
A common beginner mistake is to assume that a heavily traded strike will automatically act as support or resistance. Strike prices are reference points in the option chain, not guaranteed market levels.
Open interest, changes in open interest, volume, implied volatility, price action, and broader market conditions should be considered together before drawing conclusions.
Final Thoughts
The strike price is the foundation of an option contract. It determines the price at which the option buyer has the right to transact and plays a central role in determining whether an option is ITM, ATM, or OTM.
For NIFTY and SENSEX traders, understanding strike selection is essential before moving into more advanced concepts such as option Greeks, implied volatility, spreads, and option-chain analysis.
The goal should not be to choose the cheapest strike. The goal is to understand how the strike interacts with the underlying price, expiry, volatility, and the overall risk of the strategy.
Disclaimer
This article is for educational purposes only and does not constitute financial advice. Please consult a SEBI registered investment advisor before making any investment decisions.
This article is for educational purposes only and does not constitute financial advice. Please consult a SEBI registered investment advisor before making any investment decisions.