Glossary term
Vega
The options Greek measuring sensitivity to implied volatility; premium sellers are short vega and profit when IV falls.
Vega is the options Greek measuring how much an option's price changes per 1% change in implied volatility. Option buyers are long vega (they benefit when IV rises) and sellers are short vega (they benefit when IV falls). This is why Closelook sells premium when IV Rank is elevated — the position profits both from time decay and from the subsequent normalization of volatility. See Greeks 101 and IV Rank.