The Greeks of a whole position or account, scaled by contract count and multiplier, rather than the per-share numbers shown on a chain.
A chain quotes delta per share. A position Greek multiplies that by the options-multiplier and by how many contracts you hold, then sums across legs. Only the summed numbers tell you what a move actually costs.
Reading them in dollars is the habit that separates traders who survive from traders who are surprised. Net delta in shares, net theta in dollars a day, net vega in dollars per volatility point — three numbers that describe the account better than any list of open trades.
Example: you are short five XYZ $47.50 puts at 0.30 delta and long three $55 calls at 0.20 delta. The short puts contribute 5 × 0.30 × 100 = +150 share-equivalents and the long calls 3 × 0.20 × 100 = +60, so net delta is +210. A $1 move in XYZ is worth about $210 to the account.
Original diagrams for the ideas on this page. Illustrative, not real market data.
Delta across the range of prices. Delta says how much a call's price moves for a one-point move in the stock. Far below the strike it is near 0 and the option barely reacts; at the strike it is about 0.50; far above it approaches 1 and tracks the stock.Time decay of an option's value. The part of an option's price that is only time — its extrinsic value — drains away every day and must reach zero at expiry. The slide is gentle months out and steepest in the final weeks, which is what traders call theta.
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