What is Strike Price?
The strike price, also called the exercise price, is the fixed price at which the holder of an option can buy for calls or sell for puts the underlying asset if they choose to exercise the option. It is a fundamental parameter of every options contract that, along with expiration and current price, determines the option's value.
Strike Price and Option Value
The relationship between strike price and current asset price determines whether an option is in-the-money, at-the-money, or out-of-the-money.
For call options: In-the-money means the strike is below current price, at-the-money means the strike equals current price, and out-of-the-money means the strike is above current price. For put options, the relationships are reversed: in-the-money strikes are above current price, and out-of-the-money strikes are below.
In-the-money options have intrinsic value representing immediate exercise value. Out-of-the-money options only have time value and require price movement to become profitable.
Choosing Strike Prices
Strike selection balances cost versus probability of profit. Lower strike calls being more in-the-money are more expensive but more likely to profit. Higher strike calls being more out-of-the-money are cheaper but need larger price moves.
Traders choose strikes based on their outlook. Conservative traders often buy in-the-money or at-the-money options with higher success probability. Aggressive traders buy out-of-the-money options for potentially larger percentage returns if the underlying makes a big move.
Strike Price Intervals
Options are typically offered at standardized strike intervals. For a $50,000 BTC, strikes might be available at $45,000, $47,500, $50,000, $52,500, $55,000, and so on. The interval depends on the underlying's price and exchange conventions.
More liquid underlyings typically have more strike prices available, giving traders finer control over their exposure.
Strike Price and Greeks
Strike price significantly affects options Greeks. Delta changes dramatically with strike relative to spot. Out-of-the-money options have lower delta, in-the-money options approach 1 for calls or -1 for puts. Gamma is highest at at-the-money strikes. This means strike selection directly impacts position sensitivity to price movements.