Delta — directional exposure
Delta is the sensitivity of an option's price to a $1 move in the underlying. Long calls have positive delta (0 to 1); long puts have negative delta (-1 to 0).
Gamma — curvature
Gamma is the rate of change of delta with respect to the underlying. It peaks at-the-money and is what makes short-dated options dangerous to short.
Theta — time decay
Theta is the daily bleed from time decay. It accelerates in the last 30 days. Theta-positive books (short premium) profit in calm, range-bound markets.
Vega — vol sensitivity
Vega is the sensitivity to a 1-point move in implied volatility. Long-vega books lose money in vol crushes even when direction is correct.
Not financial advice
This lesson is educational material, not personalized advice. Examples and case studies are illustrative. Trading carries real risk of loss — never invest money you cannot afford to lose, and consult a licensed professional for guidance specific to your situation.