Understand a Long Strangle Strategy

This guide covers how a long strangle works on Nifty, the numbers on one lot, how it behaves before expiry, when to use it, how to manage it and how to automate it.

At a glance

How a long strangle works

You buy a call above the market and a put below it. Both are out of the money, so they are cheaper than at-the-money options. If the index moves sharply beyond either strike, that option gains value faster than the other loses it. If the index stays in between, both expire worthless.

The numbers on one lot

Using Black–Scholes model prices with Nifty at 25,000, 12 days to expiry, IV of 14% and a lot of 65:

• Buy the 25,300 call at ₹150.10
• Buy the 24,700 put at ₹113.40
• Net debit: ₹263.50 per unit, or ₹17,128 per lot

The index must move about 564 points up or 563 points down by expiry to break even. At 14% IV, one standard deviation of Nifty's move over 12 days is about 635 points.

How a long strangle behaves before expiry

A long strangle loses about ₹1,259 a day per lot at entry from time decay. With the index unchanged, it shows a loss of about ₹3,911 after 3 days. A fast move changes that:

• If Nifty rises 600 points in 3 days, the position shows a profit of about ₹11,700.
• If Nifty falls 800 points in 2 days, it shows about ₹17,373.

The strangle also has a vega of about +₹2,110 per lot, so a rise in IV helps it even without a move. Falls in IV after events hurt it.

When to use a long strangle

Works best when:

• A large move is expected soon, in either direction.
• IV is low relative to its usual range.
• You want to risk less than a long straddle costs.

Struggles when:

• The market stays within the strikes.
• IV falls after you buy, as it often does after scheduled events.
• The move comes slowly.

Choosing strikes

Closer strikes cost more and need a smaller move. Further strikes cost less and need a larger move. Many traders choose strikes by delta, such as buying the call and put nearest to a 0.25 delta, or by distance from the expected move. Use the option profit calculator to compare versions before you trade.

Long strangle vs long straddle

The strangle costs about half as much, so a complete loss hurts less. The straddle needs a slightly smaller move to profit. See the long straddle strategy guide for more.

Managing a long strangle

• Profit target. Sell the strangle once it reaches a target, rather than waiting for expiry.
• Time stop. Exit if the expected move has not come within a set number of days. Decay accelerates near expiry.
• Loss limit. Exit if the position loses a set share of the premium, such as 40%.
• Leg management. After a strong move, some traders sell the losing leg and keep the winning one.

Automating a long strangle

A typical automated rule set:

1. Buy the call and put nearest to a chosen delta, at a set time before an expected move, only if IV is below a chosen level.
2. Exit both legs at a profit target or a loss limit.
3. Exit both legs by a time stop, well before the final days of expiry.

Set these in QuantPower's strategy builder, test them in the backtesting engine and run them in paper trading before going live.

Common long strangle mistakes

• Buying strikes so far out that the move needed is unrealistic.
• Buying when IV is already high, ahead of a known event.
• Holding into the last days while decay takes most of the premium.
• Treating a low price as low risk. Cheap options lose their whole value more often.

Frequently asked questions

Sources

• Black, F. and Scholes, M. (1973). The Pricing of Options and Corporate Liabilities. Journal of Political Economy, 81(3), 637–654
• NSE: Equity derivatives contract specifications