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Calendar Spread Strategy

A calendar spread involves buying a longer-term option and selling a shorter-term option at the same strike to profit from accelerated time decay.

A calendar spread (also called a time spread or horizontal spread) exploits the difference in time decay between options with different expiration dates. You sell a short-term option and buy a longer-term option at the same strike price. The short option decays faster than the long option, allowing you to profit if the underlying stays near the strike price as the near-term expiration approaches.

Consider a call calendar on GOOGL at $150. You sell the $150 call expiring in 30 days for $3.00 and buy the $150 call expiring in 60 days for $5.50. Net debit: $2.50 per share ($250 per contract). After 30 days, if GOOGL is near $150, the short call expires worthless and the long call still has 30 days of time value remaining. You now hold a long call worth approximately $3.00, giving you a profit of $0.50 per share. The maximum profit occurs when GOOGL closes at the strike price at short-term expiration.

Choosing the Right Strikes and Expirations

The effectiveness of a calendar spread depends on the relationship between the two expiration dates. A typical ratio is 2:1 or 3:1, such as selling a 30-day option and buying a 60-day or 90-day option. At-the-money calendars have the highest time decay differential and the most profit potential, but they also have the most directional risk. Out-of-the-money calendars cost less but require the stock to move toward the strike. Earnings announcements between the two expirations can complicate the trade as implied volatility may spike.

Calendar Spread Variants

A diagonal spread is a calendar spread with different strike prices, combining time decay with directional bias. A double calendar involves calendars on both the call and put sides, creating a non-directional position similar to an iron condor but using time decay rather than credit collection. A calendar spread can be reversed (short the longer-term, long the shorter-term) for a debit calendar that profits from volatility expansion rather than time decay.

FAQs

What is the risk of a calendar spread?

Maximum loss is limited to the net debit paid. If the underlying moves sharply away from the strike, both options lose value and the spread can be closed or held to expiration with the loss limited to the initial cost.

How does implied volatility affect calendars?

Calendar spreads benefit from rising implied volatility because the longer-dated option has more vega exposure than the shorter-dated option. This makes them attractive when you expect IV to increase, such as before earnings.

Can I close the trade before the short expiration?

Yes. You can buy back the short option and sell the long option at any time. Many traders close at 50% of maximum profit or when the short option has decayed to a low value.

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