How is it different from a calendar?

The strikes differ, which adds a directional lean.

The debit is the maximum loss if both legs are held to the front expiration.

Strategy guide

Diagonal Spread Strategy

A diagonal spread sells a near expiration and buys a farther expiration at a different strike.

Strategy

Strategy summary

Market outlook: moderately bullish, neutral
Risk type: defined
Capital requirement: Net debit × 100
Maximum profit: Depends on strike placement and term structure
Maximum loss: Approximately the net debit
Theta / vega: positive / positive
Assignment risk: moderate
Typical use: Directional income that also leans on the volatility term structure

Payoff at expiration

Profit and loss at expirationSpot $100.00 · Breakeven $103.40

Profit LossMax profit $160.00 · Max loss -$340.00

The legs expire on different dates, so this is an approximation at the nearest expiration rather than a single-expiration payoff.

Max profit$160.00
Max loss-$340.00
Breakeven$103.40

How Diagonal works

It combines a directional lean with time decay and the volatility term structure.

Exact option legs

Sell near expiration + buy far expiration at a different strike

SELL 1 × $105.00 call expiring 2026-02-20 at $1.60
BUY 1 × $100.00 call expiring 2026-04-17 at $5.00

Payoff, breakeven and risk

At expiration the position is worth the intrinsic value of each leg. The maximum profit is $160.00, the maximum loss is -$340.00, and the position breaks even at $103.40.

Worked example

With the underlying at $100.00:

The diagonal is opened for a 3.40 net debit.
The chart is an approximation at the front expiration.

Strike selection

The long strike sets the direction; the short strike sets where income is collected.

Expiration selection

The gap between expirations drives the decay and volatility behavior.

Effect of time decay

This structure is positive on theta: net time decay works in its favour.

Effect of implied volatility

It is positive on vega: rising implied volatility helps.

Effect of stock movement

The position suits a moderately bullish or neutral view, and it is tested most when the underlying moves outside the modelled strikes.

Assignment considerations

Assignment risk is moderate. Short legs can be assigned, especially when they are in the money or before a dividend; long legs have no obligation but can be exercised.

When it works poorly

A quick move away from both strikes.
Falling long-dated volatility.
Wide long-dated spreads.

Common mistakes

Treating it as a simple spread.
Ignoring the long-dated option's lower liquidity.
Overpaying for the back-month option.

Tax caveat

Option outcomes can receive different tax treatment from share trades, and assignment changes the holding period and cost basis. This is general information, not tax advice; confirm your situation with a qualified professional.

FAQ

How is it different from a calendar?: The strikes differ, which adds a directional lean.
Is it defined risk?: The debit is the maximum loss if both legs are held to the front expiration.

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