Long Put Calendar — the time spread built from puts, with an assignment problem

What is a long put calendar?

A long put calendar sells a near-term put and buys a longer-dated put at the same strike. It is paid by the near option losing extrinsic value faster than the far one, and it needs price near the strike at the near expiration.

Key takeaways

• It is paid by the term structure and by uneven decay across two expirations.
• The real risk is early assignment of the near short put.
• The loss is roughly the debit — up to the near expiration and absent assignment.
• Break-even and maximum gain can be simulated, not calculated.

The question to answer before you open the trade: What is your plan if the near-term short leg gets exercised early?

A simple mental model: two buy-back promises with different deadlines

Imagine you give your neighbour a promise: if he brings his car round before the end of the month, you will take it off him for 10,000 €. He pays you for that promise. At the same time you have bought the very same promise from someone else — only with a ten-week deadline instead of four.

Two identical promises, two different deadlines. The difference is the whole trade:

• A four-week promise loses noticeable value with every quiet day. A ten-week promise barely moves on that same day.
• Once the short deadline passes with nothing happening, you have earned the short promise in full — and your own long promise still has six weeks of value left in it.
• You do best if the car is worth roughly what it was worth at the start.

Where the picture ends: if the car suddenly becomes worth far less, your neighbour turns up immediately — and then 10,000 € is really due, and you own a car instead of a promise. And unlike a neighbourhood arrangement, the price of both promises moves every day, because the expectation of how stormy the coming weeks will be moves with it.

How does a long put calendar work?

The driver is volatility and how it is spread across time. You sell a short-dated put and buy the same put with a longer life. Both share a strike; only their remaining lifespans differ.

The second driver is extrinsic value: it decays faster towards expiration, so the near option loses more per day than the far one. That difference is your return while price stays near the strike.

What works against you is movement in either direction. Far from the strike — up or down — both options lose their decay advantage and the gap between them shrinks. On top of that comes the path: the position is path-dependent, so how price got there matters, not only where it ended.

What separates it from the call calendar is not the shape but two details: the pricing, because volatility skew treats puts differently, and the assignment scenario. The second is where most of the surprises on this strategy come from.

If you remember one thing: a calendar is a volatility position — until the near leg is exercised, at which point it is a stock position.

How is a long put calendar constructed?

1. -1 Put @K (near expiration)
2. +1 Put @K (far expiration)

Both strikes usually sit at the money, where the decay difference between expirations is largest. The data behind this page cites 20–30 days for the near leg and 50–90 for the far one.

The construction is a net debit: the far put costs more than the near one brings in. That debit is approximately the maximum risk — with the two caveats the data states explicitly: only up to the near expiration, and only absent early exercise.

Why there is no classic payoff diagram here

The two legs expire on different days. When the near option runs out, the far one still has weeks left, and its value that day comes from remaining time, price and whatever implied volatility happens to be. This is why the data behind this page gives "by simulation only" for both the maximum gain and the break-even.

The scenario table below describes magnitudes rather than amounts. An example stock trades at 100 €. You sell the 100 € put with 25 days to run and buy the 100 € put with 70 days, paying a net 1.70 € per share, or 170 € per contract.

A modelling assumption, not a calculation: the right-hand column deliberately carries no euro amounts. What the far leg is worth at the near expiration depends on the implied volatility prevailing then.

The bottom row deserves particular attention. At 85 € the near short put is 15 € in the money with almost no extrinsic value left — exactly the configuration in which early exercise happens. Then 100 shares are in the account and 10,000 € comes due, against an original stake of 170 €.

• Run your own numbers: Break Even Multi Leg Calculator →
• Run your own numbers: Iv Percentile Calculator →

When is a long put calendar worth it?

Market phases it suits

• Sideways
• Calming down

Goal

• Trading volatility
• Hedging

A put calendar belongs in a sideways market or the calm after a volatility spike, with a longer-term bearish lean — the far long put is, after all, the position that remains.

On volatility it wants low to medium implied volatility, but the term structure is what decides it: if the near expiration is priced richer than the far one, you sell expensive and buy cheap. On puts, skew shifts the relationship between the expirations further — which is why comparing against the call version before entry is not a formality.

Its purposes are trading volatility and hedging. Read the hedging part carefully, though: the far put protects, but the sold near put works against you in a decline. As pure protection a protective put is the more honest instrument.

The greeks on a long put calendar

Short version: delta near zero, negative gamma, positive theta, positive vega. Positive theta alongside positive vega is what makes every calendar spread unusual: you sell short-dated time value that decays quickly and buy long-dated value that responds more to volatility.

Management

The time rule is: decide before the near expiration. Close, roll the near leg, or unwind — three routes, and none of them is waiting.

The put version adds a second rule that is not in the table: watch the extrinsic value of the near short put. If it drops towards zero while the put is in the money, early exercise becomes likely regardless of how many days remain.

The 20–40 % profit target is again set low. In the example, 30 % would be roughly 51 € on a 170 € stake.

Assignment and capital

Assignment risk

medium on the near-term short put

Capital required

low (equal to the debit)

Typical expiration

near leg 20-30, far leg 50-90

Typical delta

ATM

The assignment risk is medium, sits entirely on the near short put, and is the dominant risk on this strategy. The data names it as the single typical mistake: early assignment creates a stock position overnight. Concretely, 100 shares land in the account with the full purchase price due. Your far long put survives and protects those shares, but from that moment you hold a protective put with a capital requirement roughly fifty times the original debit.

The capital requirement is low in the normal case and equals the debit. That sentence only holds while the near leg is not exercised — which is why the core question on this strategy is not what it earns but what your plan is if you are assigned.

What a long put calendar does not mean

• It is not a pure bet on time. Uneven decay is only half of it. If the expected swing in the far expiration falls, your long leg loses value — and that can more than consume the entire time gain from the short leg.
• "Loss roughly the debit" only describes the undisturbed case. After early assignment you hold 100 shares and a long put. That is a different position with a different capital requirement, and the sentence no longer applies to it.
• A low capital requirement is not a small position. A 170 € stake sits opposite a 10,000 € assignment. Size this trade against the amount you would have to find, not against the debit.
• A put calendar is not a bearish position. The far long put looks bearish, the near short put pulls the other way. Net, you are paid for quiet, not for a decline.
• It is not a hedge. A sell-off makes the short leg valuable and works against you. The protection is weakest exactly when you would need it.

Which mistakes cost money on a long put calendar?

No plan for early assignment. The mistake the data names, and it hits liquidity rather than return. Putting up 170 € and owing 10,000 € overnight is not a valuation problem, it is an account problem. Establish beforehand whether your account can carry that case at all.

Read the payoff diagram as a final state. As on any calendar, the tent shape shows an estimated value at the near expiration, not an expiration result. It rests on an assumed implied volatility — change the assumption and the whole curve shifts.

Never checked the term structure. If the far expiration is priced richer than the near one, the trade starts with a handicap that has nothing to do with price. On puts, skew layers on top of that effect.

Treated as full protection. The far put protects; the sold near put does not. In a sharp decline the short leg gains value and eats exactly the part of the protection you thought you had.

Feynman check: explain a long put calendar without jargon

Explain to someone in three sentences what you are actually doing. Do it without the words "term structure", "skew", "theta" and "assignment".

Your explanation is complete when it contains four things:

1. Which two promises did you trade, and how do they differ?
2. Why does the short promise lose value faster than the long one?
3. Which price path up to the first date suits you best?
4. What happens to you if price falls hard and the other side uses its right straight away?

One possible explanation: "For four weeks I promised someone I would buy shares from them at a fixed price, and I was paid for that promise. I bought the identical promise for myself with a ten-week deadline. Short promises burn down faster than long ones, and that difference is my return. If the price falls a long way, though, I really do have to buy the shares and pay for them."

If your explanation says your risk is the money you put in, that is exactly where the gap is. Go back to the bottom row of the scenario table: at 85 € what is at stake is not the 170 € debit but a 10,000 € purchase price.

Five questions before you enter

1. Can my account carry 10,000 € if the near leg is exercised overnight?
2. Is the near expiration currently priced richer than the far one — or am I starting at a handicap?
3. How much extrinsic value is left in the near short put, and how close to the money is it?
4. On which specific date do I decide to close, roll or unwind?
5. For what I actually want, would a plain protective put be the more honest instrument?

Long Put Calendar or Long Call Calendar: what is the difference?

This data-driven table lays out the differences that actually matter between Long Put Calendar and Long Call Calendar.

Long Put Calendar compared with Long Call Calendar

Criterion	Long Put Calendar	Long Call Calendar
Market phase	Range-bound, no trend, price oscillating between levels or After a volatility spike, with a return to normal expected	Range-bound, no trend, price oscillating between levels or After a volatility spike, with a return to normal expected
What pays you	Volatility	Volatility
Risk defined	Yes	Yes
Max profit	by simulation only	no closed form - it depends on IV and remaining time
Max loss	approximately the debit	approximately the debit
Capital required	low (equal to the debit)	low (equal to the debit)
Approval level	3	3

In short: Long Put Calendar fits when the market phase is Range-bound, no trend, price oscillating between levels or After a volatility spike, with a return to normal expected and the goal is Trading volatility or Hedging; Long Call Calendar fits when the market phase is Range-bound, no trend, price oscillating between levels or After a volatility spike, with a return to normal expected and the goal is Trading volatility or Speculation.

Related strategies

These strategies solve a similar problem — the counter position is the inverse.

Long Call Calendar→

Neutral near term, bullish longer term · Time

Is the near-term expiration expensive relative to the far one (a term structure in backwardation)?

Long Put Diagonal→

Moderately bearish · Time

Does the skew even justify a put diagonal instead of a plain bear put spread?

Counter position: Long Strangle→

Direction-neutral, needs a very big move · Movement

Is the expected move large enough to reach one of the two break-evens?

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