r/options
A calendar spread profile in an options calculator is not a P&L forecast
Calendar spread P&L profiles in options calculators are snapshots based on current IV, not accurate forecasts of future expiration payoffs.
Most options calculators model a calendar spread profile at the expiration date of the front leg. And there is an important nuance here.
If an options structure is built within the same expiration cycle, the payoff profile we see at entry generally corresponds to what we will get at expiration.
With calendars, the situation is different.
The profile we see at entry and the profile we actually get by the expiration of the short legs can be quite different.
The reason is simple: a calendar is not only a bet on the underlying price movement, but also a bet on volatility. While the position is alive, IV changes, the value of the long and short options changes, and the entire shape of the position changes along with it.
The video shows exactly this kind of example.
The green dashed line is the modeled profile of a double calendar at the expiration date of the short legs, calculated at the moment the position was opened.
Then the video shows how the position actually evolved using historical option prices. It also clearly shows how changes in IV affect the value of calendar spreads. As the market dropped, IV increased, and the profile improved noticeably.
A small reminder for newer traders: when trading calendar spreads, you should not treat the expiration profile as a ready-made picture of the future.
What you see at entry is not a forecast of your future P&L. It is only a calculated snapshot based on the current market parameters.
well said
this is the kind of thing that actually helps vs the generic stuff you usually see.
Good callout. Your point generalizes to all structures that have two different expirations. Some such structures are not only about vol, but about two different time regimes.
I'd note that you point actually applies to all calculator P/Ls, regardless of structure, because every calc makes an assumption about the evolution of vol which doesn't even come close to reality. Most calcs assume constant IV across the entire timeline, which is like a mechanical clock that's stopped working. It's right twice a day, but wrong during every other moment in time.
Opsiyon hesaplayıcıları vade bitimini genellikle varsayılan bir senaryo olarak kullanır. Ancak, bir spread'in dinamiklerini anlamak için zaman değer kaybını ve volatilite etkisini farklı zaman dilimlerinde incelemek, tek bir vade sonu profiline bakmaktan daha gerçekçi bir resim sunar.
The piece people miss is that the at expiration line for the front leg silently assumes the back month's IV stays exactly where it is today. A calendar is mostly a long vega position, so the number that actually moves your result is what the back month vol does as the front expires, not the strike math. If the elevated vol you are long mean reverts, that line overstates you. Cheap fix is to re run the calculator with the back month IV knocked down a few points and see what your real downside looks like. That gives you a range instead of a single optimistic curve.
Thats why I think a vizulalizer is so important, expecially for newer ppl.
Also what happens at front month expiration majorly impacts PnL assumptions.
A debit call calendar on SPX can easily become delta positive at front expiration where the comparable spread with physically-settled ES futures options can easily become delta negative at front expiration.
Contract specs and your intention to hold the back contract can completely change or invalidate the PnL calculator
I think u are pointing out a flaw in b/s where the implied vol is assumed constant and backed out of current market price. In reality, market decides price so the implied volatility will also change and results in a different p/l line
Be aware of the wider bid-ask spread due to the four-leg structure, as well as the assignment risk on SPY. Ideally, the front-month short legs should have elevated IV relative to the back-month long legs. The goal is for front-month IV to fall while back-month IV remains stable or rises..