Vega (Volatility Sensitivity)

Vega measures the dollar change in an option's price for a 1-percentage-point change in implied volatility.

Example: A call option has a vega of 0.15 and the current IV is 30%. If IV rises to 31%, the option gains $0.15 per share ($15 per contract). If IV drops to 28%, the option loses $0.45 per share ($45 per contract).

Vega is highest for ATM options: At-the-money options have the most vega because they have the most extrinsic (time) value, which is directly affected by IV changes. Deep ITM and far OTM options have little extrinsic value, so IV changes affect them less.

Vega increases with time to expiration: A 6-month call has roughly double the vega of a 1-month call at the same strike. This is because longer-dated options have more time for volatility to impact the outcome. LEAPS (options expiring in 1-2 years) have the highest vega of any options.

Dollar impact can be enormous: On high-priced stocks, vega can be $0.50-$1.00 per contract. A 5% IV drop (common after earnings) would cause a $250-$500 loss per contract from vega alone — even if the stock moves in your favor. This is why IV crush devastates long option holders around earnings.

Long vega (buying options): You want IV to rise. Buying calls, puts, straddles, or strangles creates positive vega exposure. These positions profit when the market becomes more uncertain (IV expands). Best used before anticipated increases in volatility — before earnings season, before Fed meetings, during periods of market complacency.

Short vega (selling options): You want IV to fall. Selling covered calls, iron condors, credit spreads, or strangles creates negative vega exposure. These positions profit when volatility contracts (IV crush). Best used when IV rank is high and you expect volatility to normalize.

Hedging vega: Professional options traders manage portfolio vega carefully. If your portfolio has too much positive vega, a sudden IV drop will hurt all positions simultaneously. To hedge, sell some premium or use VIX futures. If you have too much negative vega, a volatility spike (market crash) will cause simultaneous losses across all short positions — buy protective options or VIX calls to hedge.

Calendar spreads exploit vega: In a calendar spread, the long back-month option has higher vega than the short front-month option, creating a net positive vega position. This profits when IV rises and loses when IV falls — which is why calendar spreads work best in low-IV environments where IV is likely to expand.

Vega is the most important Greek for earnings trades because IV changes around earnings dwarf most price movements.

Pre-earnings IV expansion: In the 2-3 weeks before earnings, IV typically rises 10-30% as traders buy options to bet on or hedge against the earnings move. Long option holders benefit from this vega expansion — their positions gain value even if the stock does not move.

Post-earnings IV crush: After earnings, IV collapses 30-60% overnight as the uncertainty resolves. This devastates long option positions. A stock could rise 3% and your calls still lose money because the vega loss from IV crush exceeds the delta gain from the price move.

Strategy implications: To profit from pre-earnings IV expansion, buy options 2-3 weeks before earnings and sell before the report. To profit from IV crush, sell iron condors or strangles the day before earnings. Never hold naked long options through earnings unless you expect the stock to move significantly more than the expected move priced into the straddle.

Debit spreads reduce vega risk: Bull call spreads and bear put spreads have lower vega than naked options because the short leg offsets some of the long leg's vega. This makes spreads more suitable for holding through events where IV crush is expected.