Call option explained

A call option gives its buyer the right, but not the obligation, to buy the underlying at a fixed price (the strike) until the option expires. In Indian markets calls are marked CE on the option chain. A call becomes more valuable when the underlying price rises above the strike, so buying a call is a way to profit from a rise with limited risk.

Every call has two sides. The buyer (long call) pays the premium and owns the right. The seller or writer (short call) collects the premium and must deliver the value if the buyer's right is worth something at expiry.

How a call's value is worked out at expiry

At expiry a call is worth whatever the price is above the strike, and nothing if it is below:

Call value at expiry = maximum of (underlying price − strike, 0)

For a buyer, profit is that value minus the premium paid. That gives the most important number for any call buyer, the breakeven:

Breakeven = strike + premium paid

A worked example: buying a NIFTY call

NIFTY is at 25,000. You buy the 25,100 call of the current week at ₹90. Assume a lot of 75 units (check the current lot size on NSE). You pay 90 × 75 = ₹6,750, plus charges. Your breakeven is 25,100 + 90 = 25,190.

Below 25,100 the loss stays fixed at the premium. Above 25,190 every extra point adds ₹75 to the profit. NIFTY has to rise 190 points, about 0.8%, just to break even. That is the price of limited risk.

The call seller's side

The seller of the same call receives ₹6,750. Their result is the mirror image: they keep all of it if NIFTY ends at or below 25,100, they break even at 25,190, and above that they lose ₹75 for every point. At 25,500 they lose ₹23,250, more than three times the premium they collected. Because the loss has no fixed limit, brokers ask call sellers for a large margin, often well over a lakh of rupees per NIFTY lot (check the current figure with your broker).

Sellers accept this because time is on their side: if NIFTY drifts sideways, the call loses value every day and they keep the premium. Many sellers limit the risk by buying a higher call as well, which turns the trade into a bear call spread. Investors who already own shares sometimes sell calls against them; that is a covered call.

Before expiry: what moves a call's price

Most traders close their call long before expiry, so they care about how its price moves day to day. Four things drive it:

• The underlying price (delta). A call's delta is between 0 and 1. An at-the-money call has a delta near 0.5: if NIFTY rises 100 points, the call gains about ₹50. Deep in-the-money calls move almost one-for-one; far out-of-the-money calls barely move. See the delta guide.
• Time (theta). Every day that passes takes away some time value. The decay speeds up close to expiry, especially for at-the-money options.
• Volatility (vega). If traders expect bigger moves, implied volatility rises and the call becomes more expensive even if NIFTY does not move. After events, IV often drops and calls lose value quickly.
• Interest rates and dividends matter a little: higher rates raise call prices slightly, and an expected stock dividend lowers them.

See call prices live on the chain

Here is today's NIFTY chain around the current price. The call prices are in the second column from the left:

Notice how call prices fall as strikes rise: each 50-point step up makes the target harder to reach. The shaded call prices (strikes below the current NIFTY level) have intrinsic value; the rest is only time value and can fall to zero by expiry. The same pattern holds for BANKNIFTY and stock options.

Which call to choose: near or far strikes

Cheap far calls are popular with beginners because a small amount buys many lots. But a low price reflects a low chance of paying off. The ITM, ATM, OTM guide covers the trade-offs.

When traders buy and sell calls

• Buying calls: when expecting a fairly quick rise, for example after a breakout, with risk limited to the premium.
• Selling calls: when expecting the price to stay below a level, often at strikes with large call open interest.
• Calls instead of futures: to take a bullish view without the open-ended loss of a futures position.
• Calls before a planned purchase: an investor expecting money next month can buy a call to fix the maximum price paid, at the cost of the premium.

Calls on stocks work the same way, with two differences. Lot sizes are set per stock so that one lot covers a similar rupee value, and in-the-money stock calls held to expiry are physically settled: the buyer may have to pay for and take delivery of the shares. Most traders close stock options before the last day for this reason. Calls on MCX commodities such as gold or crude oil are options on the commodity's futures contract and trade into the evening, so news from the US session moves them after NSE has closed.

A quick way to judge a call's price is to compare it with the expected move. If the market prices NIFTY to move about 250 points by expiry and your call needs a 300-point move just to break even, you are betting on a larger move than the options market expects. That can be right, but you should know it before you buy.

Common mistakes with calls

• Being right on direction but late. If NIFTY rises 150 points over two weeks, a weekly call bought on day one may still lose value.
• Buying just before an event. Implied volatility is often high before results or policy announcements, and falls right after.
• Selling naked calls without a stop. A sharp rally can wipe out many weeks of collected premium.
• Ignoring the breakeven. A call is profitable at expiry only above strike + premium, not just above the strike.