Strike Price
Definition
The strike price (or exercise price) is the fixed price at which an options contract can be exercised — for a call option, it's the price at which you can buy 100 shares; for a put, it's the price at which you can sell 100 shares — and its relationship to the current stock price determines whether the option is in-the-money, at-the-money, or out-of-the-money.
Example
“The stock was at $78. I bought the $75 strike call — $3 in the money with some extrinsic on top. Cheaper than the $80 strike but higher delta and less theta risk. Strike selection determines your risk profile as much as which direction you pick.”
Detailed Explanation
Strike price selection is one of the most important decisions in options trading, and it determines the fundamental character of the position. An in-the-money (ITM) option — a call with a strike below the current stock price, or a put with a strike above it — has intrinsic value, moves more like the underlying stock (higher delta), is more expensive, but loses less proportionally to IV changes. An out-of-the-money (OTM) option — a call above the current price — is cheaper but has zero intrinsic value, decays faster, needs a larger move to become profitable, and is more sensitive to IV changes. At-the-money options (strike ≈ current price) sit between these extremes with roughly 0.5 delta.
For directional day trades, ITM options (high delta) behave more like owning the stock — they move with price more reliably and have less extrinsic value to lose to theta. If you're trading options like a stock substitute (entering and exiting in one session), a deep ITM call with 0.8+ delta gives you near-stock-like exposure with defined risk but requires more capital. OTM options are the "lottery ticket" approach — cheap absolute cost but proportionally high risk because the entire premium can go to zero if the move doesn't materialize, while theta and potential IV crush work against you the entire time you hold.
Strike selection also affects your breakeven point at expiration. A call with a $75 strike and $4.00 premium requires the stock to be above $79 at expiration for you to profit at expiration. If you're day trading and closing well before expiration, this matters less than the delta and current premium movement, but understanding the full picture — intrinsic vs. extrinsic, breakeven, probability of expiring in-the-money — gives you a complete view of what you own before you buy it. Strike selection isn't just about cost; it's about matching the option's risk profile to your actual directional thesis and time horizon.