With earnings season unbelievably upon us in a few short weeks, it might be a good time to talk about a subject that is brought up quite often in MTM Group Coaching and Online Education and is often debated by option traders learning to trade advanced strategies; double calendars vs. double diagonals.
Double Calendars vs. Double Diagonals
Both double calendars and double diagonals have the same fundamental structure; each is short option contracts in nearby expirations and long option contracts in farther out expirations in equal numbers. As implied by the name, this complex spread is comprised of two different spreads. These time spreads (aka known as horizontal spreads and calendar spreads) occur at two different strike prices. Each of the two individual spreads, in both the double calendar and the double diagonal, is constructed entirely of puts or calls. But the either position can be constructed of puts, calls, or both puts and calls. The structure for each of both double calendars or double diagonals thus consists of four different, two long and two short, options. These spreads are commonly traded as “long double calendars” and “long double diagonals” in which the long-term options in the spread (those with greater value) are purchased, and the short-term ones are sold. The profit engine that drives both the long double calendar and the long double diagonal is the differential decay of extrinsic (time) premium between shorter dated and longer dated options. The main difference between double calendars and double diagonals is the placement of the long strikes. In the case of double calendars, the strikes of the short and long contracts are identical. In a double diagonal, the strikes of the long contracts are placed farther out-of-the-money) OTM than the short strikes.
Why should an option trader complicate his or her life with these two similar structures? The reason traders implement double calendars and double diagonals is the position response to changes in IV; in other words, the vega of the position. Both trades are vega positive, theta positive, and delta neutral—presuming the price of the underlying lies between the two middle strike prices—over the range of profitability. However, the double calendar positions, because of the placement of the long strikes being closer to ATM, responds favorably more rapidly to increases in IV while the double diagonal responds more slowly. Conversely, decreases in IV of the long positions has a negative impact on double calendars more strongly than it does on double diagonals.
If you have only traded a single-legged calendar or diagonal through earnings season even not during earnings season, it might just be time to give them a look. Maybe you have never traded a calendar or a diagonal. This might be the time to find out about these time spreads. Once a single position spread makes sense, a double might make even more sense and be more profitable too.
Senior Options Instructor