The most common complaint from new option buyers goes like this: “The stock went up after earnings, and my call still lost money.” Nothing was wrong with the broker. Before a report, options are priced for a large move. Once the news is out, implied volatility collapses and takes the option’s price with it. The Greek that measures that exposure is vega. On October 6, 2026 the VIX closed at 15.00, near the bottom of its one-year range, which makes this a good moment to understand which side of vega your positions sit on. For all four Greeks together, see the options Greeks explained.
What is vega in options?
Vega is the change in an option’s price for a 1-percentage-point change in implied volatility, with everything else held constant. A vega of 0.114 means the option gains about 11.4 cents per share, or $11.40 per contract, if implied volatility rises from 30% to 31%, and loses the same if it falls to 29%.
Implied volatility is the volatility number that makes a pricing model match the option’s market price. It is the market’s price of uncertainty. When investors are nervous, they pay up for options and implied volatility rises; when they are calm, it falls. Vega converts those swings into dollars.
A 10-point move is common around events. Take a 30-day at-the-money option on a $100 stock: at 30% implied volatility it is worth $3.59; at 40% it is worth $4.73, a 32% gain without the stock moving at all. Vega is the same for a call and a put at the same strike and expiry, and always positive for the owner.
How does vega change with time to expiration?
Vega grows with the square root of time to expiry, so long-dated options carry far more of it. A one-year at-the-money option has about seven times the vega of a one-week option on the same stock.
This has two consequences that surprise people:
- LEAPS are volatility trades. An 80-delta, one-year Nvidia call near the $193 strike, at an assumed 40% implied volatility, has a vega of about $0.67 per share. A 10-point drop in implied volatility costs about $670 per contract with no move in the stock. See the LEAPS guide and the poor man’s covered call for how to account for it.
- Short-dated options are mostly about gamma. A one-week option has little vega; what moves it is the stock, through gamma, and time, through theta.
Vega also peaks at the money and falls away for deep in-the-money and far out-of-the-money strikes, which carry less time value for a volatility change to reprice.
| Days to expiry | 90 strike (in the money) | 100 strike (at the money) | 110 strike (out of the money) |
|---|---|---|---|
| 7 | $0.002 | $0.055 | $0.004 |
| 30 | $0.049 | $0.114 | $0.068 |
| 90 | $0.138 | $0.196 | $0.175 |
| 365 | $0.326 | $0.383 | $0.399 |
Read the table across and down. Short-dated vega is concentrated at the strike, while one-year vega is almost flat across strikes: a long-dated option of almost any strike is a large position in implied volatility.
What is IV crush, and why does it happen after earnings?
IV crush is the sharp drop in implied volatility once a known event has passed. Before earnings, near-dated options must price in the chance of a big gap, so their implied volatility is inflated. After the report the uncertainty is resolved, implied volatility falls back toward normal, and option prices drop through vega.
Walk through the chart. Nvidia closed at $240.20 on October 6, 2026. Suppose four days before a report a 240-strike call is priced at 60% implied volatility: it costs about $6.17 per share. The next day implied volatility is back to 35%:
- Stock flat: the call is worth about $3.18, a loss of nearly half.
- Stock up 3%: about $8.17, a gain, but smaller than the move suggests.
- Stock up about 2%: roughly breakeven. Anything less and the buyer loses despite being right on direction.
- Stock down 3%: about $0.72, nearly a total loss.
The implied volatility levels here are round, illustrative assumptions, not quotes. The pattern is real, and it is why the options market’s “expected move” (roughly the at-the-money straddle price) is the bar a buyer has to clear. For trading the event itself, see straddles and strangles for earnings.
Buying short-dated calls the day before earnings is a bet that the stock moves more than the market already expects, not just in your direction. Academic evidence on whether pre-earnings options are too cheap or too rich is mixed and varies by stock and period, so treat the expected move as a fair hurdle to clear, not a gift.
Which positions are long or short vega?
Positions that own options are long vega and gain when implied volatility rises; positions that sell options are short vega and gain when it falls. Spreads net the two legs.
Calendar spreads are the interesting exception. You sell a near-dated option and buy a longer-dated one at the same strike; because the longer-dated leg carries more vega, the spread is net long vega even though you sold something. That makes calendars a way to own volatility cheaply when it is low. See calendar and diagonal spreads.
For investors running covered calls across several holdings, vega adds up quietly. Ten 30-delta, 45-day covered calls on Nvidia at 40% implied volatility carry about $290 of short vega per point: a 10-point volatility spike, common in a selloff, adds roughly $2,900 to the cost of buying them back, on top of any move in the stock.
When should you buy or sell vega?
Buy vega when implied volatility is low relative to its own history, and sell it when it is high. Implied volatility mean-reverts: spikes fade and calm periods end. The cleanest way to measure “low” and “high” is IV rank or IV percentile.
- Low IV (IV rank under about 20): premium is cheap. Hedges such as protective puts cost less, and long-vega structures (debit spreads, calendars) are attractive. On October 6, 2026 the VIX’s one-year IV rank was about 9.
- High IV (IV rank above about 50): premium is rich. Covered calls, cash-secured puts and defined-risk credit spreads get paid more for the same risk.
- Events: implied volatility rises into earnings and FOMC meetings and drops after. Sell into the event only with defined risk; buy only if you expect a move bigger than the one priced.
Hedging is cheapest when nobody wants it. A VIX near its one-year low is the time to put protection on, not the time to remove it; see VIX volatility regimes.
Does a VIX of 15 mean options are cheap?
A VIX of 15 means the S&P 500 options market is pricing about a 15% annualized move, or roughly 0.9% a day (15 ÷ √252), over the next 30 days. Whether that is cheap depends on what actually happens. Implied volatility has tended to run above the volatility that is later realized, which is the premium option sellers collect, but in sudden selloffs realized volatility can be several times what was priced.
Low implied volatility is therefore an opportunity for buyers of protection and a warning to sellers: a short-vega book opened at a VIX of 15 has more room to be hurt by a spike than one opened at 30. For the index-wide view of who is long and short volatility, see gamma exposure (GEX).
What should you check about vega before a trade?
- Read vega and convert it to dollars: vega × 100 × contracts, per vol point.
- Check implied volatility against its range: IV rank and IV percentile.
- Check the calendar: earnings, FOMC, CPI and other events before expiry.
- For buyers: compare the expected move priced into the straddle with the move you expect.
- For sellers: stress-test the position for a 10-point implied-volatility spike.
- Sum vega across all positions and decide whether your portfolio should be net long or short volatility right now.
Frequently asked questions
What is vega in options in simple terms?
Vega measures how much an option's price changes when implied volatility changes by 1 percentage point. If an option has a vega of 0.20, it gains about 20 cents per share, or 20 dollars per contract, when implied volatility rises from 30 to 31 percent, and loses the same amount if it falls to 29 percent.
What is IV crush?
IV crush is the sharp fall in implied volatility after a known event such as earnings. Before the report, options are priced for a big move; afterwards that uncertainty is gone, so implied volatility drops and option prices fall even if the stock moves. Long options lose through vega; short options gain.
Does vega increase or decrease as expiration approaches?
Vega decreases as expiration approaches. It grows roughly with the square root of time, so a one-year at-the-money option has about seven times the vega of a one-week option. That is why long-dated options and LEAPS are as much a volatility trade as a directional one.
Is vega the same for calls and puts?
Yes. For the same strike, expiry and underlying, a call and a put have the same vega, and it is positive for both when you own them. A rise in implied volatility increases the price of both calls and puts.
Which strategies are short vega?
Covered calls, cash-secured puts, credit spreads, iron condors and short straddles are short vega: they gain when implied volatility falls and lose when it rises. Long calls, long puts, long straddles and calendar spreads are long vega.
How do I avoid IV crush when buying options?
Avoid buying short-dated options right before earnings unless you expect a move larger than the one priced in. Alternatives include buying after the report, using spreads so the short leg offsets much of the vega, or using longer-dated options where the event is a smaller share of total implied volatility.
Key takeaways
- Vega is the dollar change per 1-point move in implied volatility: about $0.11 for a 30-day at-the-money option on a $100 stock.
- It grows with time to expiry and peaks at the money: long-dated options are mostly volatility trades.
- Buyers are long vega and sellers are short vega; calls and puts at the same strike have the same vega.
- IV crush after earnings can leave a call buyer losing money on a correct call: in our Nvidia example the stock had to rise about 2% just to break even.
- Buy vega when IV rank is low, sell it when IV rank is high, and size short-vega positions for volatility spikes.
- Add up vega across the portfolio: covered calls on several names can leave you meaningfully short volatility.
Sources and method
- Cboe, VIX Index — how the VIX measures 30-day implied volatility on the S&P 500
- OCC, Characteristics and Risks of Standardized Options — option pricing factors, including volatility
- FINRA, Options — options risks for retail investors
- SEC Investor.gov, Options (glossary) — basic option definitions
- Black and Scholes (1973), The Pricing of Options and Corporate Liabilities — the model behind every vega figure
Vega and price figures use Black–Scholes for a non-dividend stock with a 4% rate; generic examples use a $100 stock at 30% implied volatility. The Nvidia earnings example uses the October 6, 2026 close of $240.20 with assumed implied volatility of 60% before and 35% after a report; these are round illustrative levels, not quotes. VIX figure is the Cboe close via Yahoo Finance.