Delta (Options)

Delta is the most fundamental of the option Greeks, measuring the rate of change of an option's price relative to a $1 change in the underlying asset. Call options have positive deltas (0 to 1.0) and put options have negative deltas (0 to -1.0). An at-the-money call typically has a delta around 0.50, meaning the option price rises approximately $0.50 for every $1 increase in the stock. Deep in-the-money options approach a delta of 1.0 (or -1.0 for puts), behaving almost like the stock itself. Delta also serves as a rough proxy for the probability that the option will expire in the money — a 0.30 delta call has roughly a 30% chance of being profitable at expiration. Delta is used extensively for position sizing, hedging, and portfolio risk management.