IV crush is the sharp drop in implied volatility after a scheduled event like an earnings report, and it can shrink an option's price even when the stock moves the way the buyer wanted. Before the report, options are priced for uncertainty. Once the numbers are out, that uncertainty is gone, and the premium that paid for it drains out of the option, often by the next open. When the stock's actual move comes in smaller than the move the options were priced for, the volatility drop usually outweighs the directional gain.
That's the trap in one paragraph. The rest is arithmetic: how big the priced-in move is, how much of the premium is event premium, and what has to happen for an option bought before the report to hold its value.
What IV Crush Actually Is
Implied volatility (IV) is the volatility number that, fed into a pricing model, reproduces an option's market price. Higher IV means a more expensive option, all else equal. It is the market's price for uncertainty, quoted as an annualized percentage.
Earnings are the obvious source of that uncertainty. The Options Industry Council (OIC), whose education site is published by The Options Clearing Corporation, calls an earnings release "one of the biggest scheduled uncertainty events for stocks" and notes that IV typically rises steadily in the weeks before the announcement. Once the result is public, options reprice quickly. In the OIC's words, volatility crush "isn't a flaw in the options market" but "the market doing its job."
The Greek that measures the damage is vega. The OIC defines vega as an option's sensitivity to changes in implied volatility. Anyone who owns options is long vega. When IV falls 40 or 50 points overnight, that line of the P&L goes negative fast, and it can swamp whatever the stock's move added through delta.
The OIC Example: Right Direction, Losing Trade
The OIC walks through a textbook case. A stock trades at $100 the day before earnings. A trader buys the $105 call for $2.90 with IV at 80%. The next day the stock rises to $106, and the call is worth $2.10, because IV has collapsed to 30%.
| Item | Before the report | After the report |
|---|---|---|
| Stock price | $100 | $106 (+6%) |
| Implied volatility | 80% | 30% |
| $105 call price | $2.90 | $2.10 (−27.6%) |
| Intrinsic value | $0.00 | $1.00 |
| Time (extrinsic) value | $2.90 | $1.10 |
Source: OIC example figures; the intrinsic and time-value split is our arithmetic. The stock gained 6% and the call lost 27.6%. The $1.00 of intrinsic value the move created was overwhelmed by the time value that disappeared, which fell from $2.90 to $1.10, a 62% haircut. Direction was right. Pricing was the problem.
A Hypothetical Straddle, Run Through the Math
To see how move size and the crush interact, here is a hypothetical setup. These are not market quotes. They are outputs of the standard Black-Scholes model with zero interest rate and no dividends.
- Hypothetical stock at $100, reporting after the close.
- At-the-money $100 straddle (one call plus one put), 7 calendar days to expiration.
- Pre-report IV: 90%. Post-report IV: 35%, with 6 days left.
At 90% IV the model prices the call and the put at $4.97 each, so the straddle costs $9.94. That is the market's priced-in move: roughly ±$9.94, or about 9.9%, by expiration. Run the expected move formula on the same inputs and you get a one-standard-deviation move of $100 × 0.90 × √(7/365) ≈ $12.46. The straddle is about 0.798 times that, the standard straddle-to-1-SD ratio.
Now the report hits and IV drops to 35%. Here is what the same straddle is worth at different stock prices:
| Stock after report | Move | Straddle value | Change vs. $9.94 |
|---|---|---|---|
| $100 | 0% | $3.58 | −64% |
| $95 | −5% | $5.55 | −44% |
| $105 | +5% | $5.65 | −43% |
| $110 | +10% | $10.06 | +1% |
| $112 | +12% | $12.02 | +21% |
Hypothetical inputs; Black-Scholes values with 6 days left at 35% IV.
Read the middle rows. A 5% move in either direction is a real, headline-worthy reaction, and it still cost the straddle about 43% to 44%. The stock moved roughly half as much as the options had priced, and the IV collapse did the rest. The position only gets back to even near a 10% move, which is roughly the straddle price. That's the logic behind every "implied move" on an options screen: the straddle price is the bar the stock has to clear.
A single call tells the same story. In this hypothetical, the $100 call bought at $4.97 is worth $5.32 after a 5% rally, a gain of about 7%. Had IV stayed at 90%, the model puts that call at $7.63. The crush took $2.31 off the value of a call on a stock that went the right way.
One caveat that matters: real chains have skew, wide bid-ask spreads around events, and a post-report IV nobody knows in advance. The table shows the shape of the risk, not a forecast for any stock.
How Traders Size It Up Before the Report
Nobody can know the post-report IV ahead of time. What traders can measure is how much event premium is sitting in the chain, and how that compares with what the stock has delivered before. The usual checklist:
- The implied move. The at-the-money straddle in the first expiration after the report, divided by the stock price. A $9.94 straddle on a $100 stock prices roughly a 9.9% move. That's the number the stock has to beat.
- The stock's own history. Traders compare the implied move with the stock's actual post-earnings moves over past quarters. If realized moves have usually come in under the implied, the premium has historically been rich. If they've often blown through it, it hasn't. A clue, not a verdict: one guidance cut changes the pattern.
- The term-structure kink. The expiration that captures the report usually carries noticeably higher IV than the next one out. The gap is a rough measure of the event premium, and it's the part that tends to vanish once results are out.
- IV rank and IV percentile. The OIC describes IV rank as placing current IV on a 0 to 100 scale against its past-year range, and IV percentile as the share of time IV sat below the current level. Neither predicts direction. They answer whether the current premium is high for this stock.
- Vega exposure by expiration. Per the OIC, longer-term options tend to have higher vega. But the front expiration usually takes the biggest IV drop, because the event is a bigger share of its remaining life. Traders check both before picking a tenor.
For how these numbers looked in real setups, see how options traders braced for a Chipotle earnings move and how they positioned ahead of Micron's post-market report. In both, the question underneath is the same: is the priced-in move too big or too small?
A Real Spike-and-Fade: VIX9D, October 2026
We don't have single-stock option chains for this piece, but the same build-and-deflate pattern shows up at the index level. The Cboe S&P 500 9-Day Volatility Index (VIX9D) tracks 9-day implied volatility from S&P 500 index options. This is not an earnings example. It is short-dated, index-wide implied volatility, and it shows how quickly near-term premium can inflate and then leak out.
| Close | VIX9D | VIX (30-day) | VIX9D minus VIX |
|---|---|---|---|
| October 12, 2026 | 11.68 | 15.21 | −3.53 |
| October 14, 2026 | 14.59 | 16.87 | −2.28 |
| October 16, 2026 | 20.12 | 19.99 | +0.13 |
| October 19, 2026 | 17.93 | 18.44 | −0.51 |
| October 21, 2026 | 15.49 | 16.68 | −1.19 |
Source: Cboe VIX9D and VIX daily history files.
VIX9D climbed from 11.68 at the October 12, 2026 close to 20.12 at the October 16 close, a 72% jump in four sessions. The 30-day VIX rose about 31% over the same stretch. By the October 21 close VIX9D was back at 15.49, giving back 4.63 points, more than half of the 8.44-point run-up, in three sessions.
On October 16 the short end briefly closed above the 30-day VIX. Since January 2011, VIX9D has closed above VIX on 1,042 of 3,980 sessions, or 26.2%. The shorter the horizon, the more a near-term scare dominates its price, and the faster that premium bleeds once the scare passes. Earnings IV in single-stock front-week options tends to follow the same shape, often more violently. For more on reading the curve, see our guide to VIX term structure.
More options and volatility breakdowns live on the Wall Street War Room desk.
Desk Notes
What the numbers say: Event premium is measurable before the report. The straddle sets the bar, and in the hypothetical a 5% move still left a straddle down about 43%. Index-level short-dated IV showed the same spike-and-fade in October 2026, with VIX9D up 72% and then giving back more than half of the jump within three sessions.
What they don't: No formula tells you how much IV drops or how far the stock will move. A stock's past earnings reactions are a reference, not a promise, and skew, spreads and liquidity make real chains messier than any model table.
FAQ
Does IV crush happen after every earnings report?
Implied volatility typically falls once results are out, because the scheduled uncertainty has been resolved. The size varies widely. If the report raises new questions, such as a guidance surprise, IV can stay elevated longer.
Why can a call lose money if the stock goes up?
Because the option's price is intrinsic value plus time value, and the time value was inflated by pre-report IV. In the OIC example the stock rose 6% and the $105 call fell from $2.90 to $2.10 as IV dropped from 80% to 30%.
Is IV crush the same as time decay?
No. Time decay (theta) is value lost as expiration approaches. IV crush is value lost because the volatility input fell. Both hit overnight after a report, but in event setups the IV drop is usually the larger piece.
How do traders estimate the move the market is pricing?
The quick version is the at-the-money straddle in the first expiration after the report, divided by the stock price. The longer version uses price × IV × √(days/365); our expected move formula guide works through both.