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theta decay
What does theta decay mean?
The loss of an option's extrinsic value over time as it nears expiration. It works against buyers and in favor of sellers.
"My calls were right on direction but theta decay killed them."
Origin
Standard options terminology named for the Greek letter 'theta'; ubiquitous in WSB options talk.
Frequently asked questions
What is theta decay?
It's the gradual loss of an option's extrinsic (time) value as it approaches expiration. Each day that passes chips away at what the option is worth, all else being equal.
Does theta decay help or hurt me?
It hurts option buyers, since the value they paid for erodes over time, and it helps option sellers, who profit as that value drains away.
Why is it called 'theta'?
Theta is one of the option 'Greeks,' named after the Greek letter, and it specifically measures how much an option's price is expected to fall per day from the passage of time.
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