How does the color Greek describe gamma decay?

Q: How does the color Greek describe gamma decay?

Color is the derivative of gamma with respect to time, sometimes written DgammaDtime. It measures how gamma itself decays or grows as expiration approaches, holding spot and volatility fixed. For at-the-money short-dated options, gamma actually rises into expiry before collapsing at maturity, while deep OTM options see gamma steadily decay to zero.\n\nImagine a portfolio at a Dublin boutique called Glenmara Derivatives long 500 at-the-money weekly straddles. Gamma today might be 0.16 per share. Color could be plus 0.009 per day for the next two days, meaning gamma rises to 0.169 then 0.178 as expiry approaches, sharpening the convexity and magnifying both gains on moves and losses on pin risk. After that peak, color flips sharply negative, and gamma collapses into expiry Friday.\n\nFor OTM options, color is negative throughout: a 3% OTM call two weeks from expiry has gamma 0.04 decaying at color minus 0.002 per day, so by day seven gamma has halved. Portfolio managers who are net short gamma near expiration must recognize that color compounds the danger: hedging costs explode because every point of gamma drifts up day by day. CFA candidates should pair color with theta conceptually: theta is how value bleeds, color is how gamma ripens, and together they describe the temporal geometry of options.

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AcadiFi · Accepted Answer

Color is the derivative of gamma with respect to time, describing how gamma itself ripens or decays as expiration approaches.

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Imagine a portfolio at a Dublin boutique called Glenmara Derivatives long 500 at-the-money weekly straddles. Gamma today might be 0.16 per share. Color could be plus 0.009 per day for the next two days, meaning gamma rises to 0.169 then 0.178 as expiry approaches, sharpening the convexity and magnifying both gains on moves and losses on pin risk. After that peak, color flips sharply negative, and gamma collapses into expiry Friday.

For OTM options, color is negative throughout: a 3% OTM call two weeks from expiry has gamma 0.04 decaying at color minus 0.002 per day, so by day seven gamma has halved. Portfolio managers who are net short gamma near expiration must recognize that color compounds the danger: hedging costs explode because every point of gamma drifts up day by day. CFA candidates should pair color with theta conceptually: theta is how value bleeds, color is how gamma ripens, and together they describe the temporal geometry of options.

How does the color Greek describe gamma decay?

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