The "Greeks" describe how an option's price is expected to change based on different factors. For covered call sellers, you only need to focus on the two most important ones — Delta and Theta. The others (Gamma and Vega) are less critical for our mechanical approach.
Delta — the most important Greek for covered calls
Delta tells you how much an option's price is expected to move when the stock price moves by $1. Delta ranges from 0.00 to 1.00 for calls; a 20 Delta call moves about $0.20 when the stock moves $1.
- We target ~20 Delta calls (or near the 1 Standard Deviation strike) — roughly 80%+ probability the call expires worthless. We keep the full premium and our shares most of the time.
- As the stock rises, the delta of our short call increases. When delta reaches 20–30, we usually roll the call up and out for a net credit.
- Delta is our main risk gauge: low delta = safer, higher probability. Higher delta = the call is getting closer to being exercised and we should consider rolling.
- The lower the delta when we sell, the more "insurance" we have that we keep both the premium and our shares.
Theta — our best friend as covered call sellers
Theta measures how much an option's value decreases each day due to time passing. When you sell a call, you have positive theta — you make money every day the stock stays relatively flat, even if the price doesn't move at all.
Theta is the reason covered calls work so well. Time decay accelerates as expiration approaches, which is why we prefer 30–45 day trades for the active style. Every day that passes without the stock moving dramatically puts more of the premium in our pocket.
Vega — volatility
Vega tells you how much an option's price changes when implied volatility changes by 1%. When you sell a call, you are short vega. If volatility spikes (market scare, earnings), the value of the call you sold can temporarily increase, showing a paper loss. This is usually temporary — volatility tends to drop back down, and theta does its work. We don't worry much about Vega day-to-day, but it explains why we prefer selling when IVR is higher (more premium to collect).
Gamma — not critical for our style
Gamma measures how quickly Delta changes when the stock moves. It matters most for very short-term or at-the-money trades. For our mechanical covered-call approach (20 Delta, 30–45+ DTE), Gamma is not something we need to watch closely.
Delta = our probability and risk gauge (target ~20 Delta when selling).
Theta = our daily paycheck (positive theta works in our favor every day).
Focus on these two Greeks and you have everything you need to trade covered calls with confidence and mechanical precision.