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Trading & Risk

Choosing Strikes and Expiries

Pomegra Learn

Choosing Strikes and Expiries

Every options trade begins with a decision: which strike and which expiration? These two choices shape everything that follows—your profit potential, your time horizon, your risk exposure, and the probability of success. Experienced traders develop intuition about these selections through years of observation, but the intuition rests on a foundation of mechanical principles that you can understand immediately.

Strike selection is not arbitrary. The relationship between strike price and current spot price determines the option's moneyness, and that determines its Greeks—especially delta and gamma. Delta tells you the option's sensitivity to price moves. An at-the-money (ATM) call with 50 delta means a dollar move in the underlying will change the option's price by roughly 50 cents. An out-of-the-money (OTM) call with 20 delta moves more slowly and costs less upfront, but decays faster as time passes and has sharper payoff cliffs. Strike choice is a trade-off between probability (how often you want to be right), premium capture (how much decay works in your favor), and directional exposure (how much delta you accept).

Expiration choice is equally consequential. A short-term option—say, 5 days to expiration—experiences intense theta decay; time decay works dramatically in your favor if you're selling, or violently against you if you're buying. A longer-dated option—30 or 60 days—decays more slowly and gives your thesis more time to play out, but requires stronger conviction and locks capital away for longer. The shape of the theta curve is not linear; decay accelerates as expiration approaches, and the last week of an option's life is where dramatic changes occur.

Gamma compounds these effects. Gamma is the rate of change of delta, and it rises as you move closer to expiration and closer to the strike price. An OTM option purchased deep out-of-the-money has low gamma and low theta; price movement barely changes its delta, and time decay is slow. But a short-dated ATM option has very high gamma and very high theta; the slightest move in the underlying swings delta dramatically, and decay is relentless. Understanding this relationship guides your choice: do you want leverage (high gamma, short-dated, OTM) or stability (low gamma, longer-dated, ATM)?

Position sizing should be calibrated to the Greeks of your chosen strike and expiration, not just to the price of the option itself. Buying a 50-delta call that costs $200 is fundamentally different from buying a 20-delta call that costs $50. The first position is nearly synthetic-long; the second is a lottery ticket with higher leverage. Your portfolio's delta, gamma, and theta exposure all hinge on these choices. Professional traders often think in terms of Greeks first and price second; they might say "I want to buy a 40-delta call" and then check the price, rather than "I want to spend $500" and accept whatever position emerges.

The chapters ahead dig into specific frameworks for making these decisions: how to use delta as a probability proxy, how to read the decay landscape for different time horizons, and how to size a position so that it suits your risk tolerance and market view. You will learn to interpret the trade-offs visually, through profit-and-loss diagrams, and to recognize when a short-dated OTM position is the right play versus when you need patience and capital staying power with longer-dated strikes closer to the money.

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